To see the other types of publications on this topic, follow the link: Isoenzymes.
Journal articles on the topic 'Isoenzymes'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Isoenzymes.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Sharma, R. K., and J. Kalra. "Characterization of calmodulin-dependent cyclic nucleotide phosphodiesterase isoenzymes." Biochemical Journal 299, no. 1 (April 1, 1994): 97–100. http://dx.doi.org/10.1042/bj2990097.
Full textAbstract:
Calmodulin-dependent phosphodiesterase (CaMPDE) is one of the key enzymes involved in the complex interactions which occur between the cyclic-nucleotide and Ca2+ second-messenger systems. Calmodulin-dependent phosphodiesterase exists in different isoenzymic forms, which exhibit distinct molecular and/or catalytic properties. The kinetic properties suggest that the 63 kDa brain isoenzyme is distinct from the brain 60 kDa and heart and lung CaMPDE isoenzymes. The CaMPDE isoenzymes of 60 kDa from brain, heart and lung are regulated by calmodulin, but the affinities for calmodulin are different. At identical concentrations of calmodulin, the bovine heart CaMPDE isoenzyme is stimulated at a much lower Ca2+ concentration than the bovine brain or lung isoenzymes. The bovine lung CaMPDE isoenzyme contains calmodulin as a tightly bound subunit, so that a change in calmodulin concentration had no effect on the [Ca2+]-dependence of activation of this isoenzyme. These observations are consistent with the notion that differential regulation by calmodulin and Ca2+ is an important function of these isoenzymes, which provide fine-tuning mechanisms for calmodulin action.
2
Parviainen, M. T., J. H. Galloway, J. H. Towers, and J. A. Kanis. "Alkaline phosphatase isoenzymes in serum determined by high-performance anion-exchange liquid chromatography with detection by enzyme reaction." Clinical Chemistry 34, no. 12 (December 1, 1988): 2406–9. http://dx.doi.org/10.1093/clinchem/34.12.2406.
Full textAbstract:
Abstract This rapid, reproducible method for separating and determining individual alkaline phosphatase (EC 3.1.3.1) isoenzymes in serum is based on high-performance liquid chromatography with a weak anion-exchange column (SynChropak AX 300). The isoenzymes so resolved are detected by using an on-line enzyme reaction followed by spectrophotometric monitoring at 405 nm of the 4-nitrophenol formed. Complete diagnostic profiles of the various isoenzymes present in normal and pathological sera are obtained within 20 min. The mean (and SD) normal concentrations of the bone B1 and intestinal isoenzymes in serum of adults were 3.7 (4.3) and 4.5 (3.9) U/L, respectively (n = 14), and of the bone isoenzyme B2 and liver isoenzymes L1 and L2, 5.8 (8.6), 33.0 (10.6), and 12.0 (4.8) U/L, respectively (n = 17). Concentrations of the B2 and L1 isoenzymes in adults over age 40 years differed significantly from those in adults younger than 40 years, that of bone isoenzyme being lower (P less than 0.05) and that of the liver isoenzyme being higher (P less than 0.001) in the younger adults.
3
Schreiber, W. E., and L. Whitta. "Alkaline phosphatase isoenzymes resolved by electrophoresis on lectin-containing agarose gel." Clinical Chemistry 32, no. 8 (August 1, 1986): 1570–73. http://dx.doi.org/10.1093/clinchem/32.8.1570.
Full textAbstract:
Abstract With this electrophoretic method the liver, biliary, and bone isoenzymes of alkaline phosphatase are clearly separated on agarose gels. Wheat-germ lectin, incorporated in the gel matrix, binds the bone isoenzyme selectively, forming a precipitate near the origin. Neither liver nor biliary isoenzyme is affected. Activity staining with an indigogenic dye substrate reveals the liver isoenzyme migrating nearest the anode, followed by the biliary and bone isoenzymes. Results are generally similar to those of electrophoresis on cellulose acetate. However, the lectin-agarose gels better resolve the liver and bone isoenzymes, and heat treatment of samples is not required before electrophoresis.
4
Balogun, Kayode, Megan Lee, and Kelly Doyle. "Comparison of Heat Fractionation and Gel Electrophoresis Methods for the Quantitative Determination of Alkaline Phosphatase Isoenzymes." American Journal of Clinical Pathology 154, Supplement_1 (October 2020): S8. http://dx.doi.org/10.1093/ajcp/aqaa137.014.
Full textAbstract:
Abstract Introduction Alkaline phosphatase (ALP) is important in the diagnostic work-up for hepatobiliary and bone diseases. ALP isoenzymes are expressed in the bone, liver, kidney, placenta, and intestine, and vary in heat stability and electrophoretic mobility. Distinguishing the different ALP isoenzymes is clinically important for the diagnosis of pathologies associated with elevated ALP activity. Current modalities available to measure ALP isoenzymes utilize the heat stability, electrophoretic mobility, and immunochemical properties of the isoenzymes. The differences inherent in these methods allow for unique benefits of each method in identifying ALP isoenzymes. The objective of this study was to compare bone, liver, and placental ALP isoenzyme results determined by heat fractionation and gel electrophoresis and to characterize the heat-stable non-liver fraction (t1/2 >11 min), reported by heat fractionation, using gel electrophoresis. Methods A total of 72 de-identified serum samples that span a wide range of known ALP isoenzyme concentrations and disease states were used to measure ALP using gel electrophoresis and heat fractionation. Heat fractionation was achieved by selective inactivation of the isoenzymes at 56 °C in 10, 15, and 20-minute intervals. Log-percent activity of the total and heat-inactivated fractions at each time point was plotted against time in minutes. The linear activity decay between 10 and 20 minutes determined the relative amount of liver isoenzyme activity and the slope of the line determined the half-lives of ALP isoenzymes. Electrophoresis was performed according to the manufacturer’s protocol using the Hydragel ISO-PAL gel to resolve ALP isoenzymes based on their electrophoretic mobility and interaction with lectin. ALP isoenzymes were quantified by densitometry. Results Our results show a significant correlation coefficient (r) of 0.98, Deming regression slope of 1.1, and bias of -1.2% for the liver isoenzyme (n=43). However, liver fractions are not distinguishable by heat fractionation when heat-stable isoforms are present. The bone fraction (n=43) showed a coefficient of correlation of 0.86, slope of 0.55, and bias of -31%. Although, with a small sample size (n=6), the placental isoenzyme showed a significant agreement between the two methods: r = 0.999, slope = 0.98, and a -3.5% bias. Of the non-liver fractions reported by heat fractionation (n=13, ALP >100 U/L) eleven (85%) showed distinct qualitative bands in the intestinal lane on gel electrophoresis; however, quantitative values did not correlate between the two methods. Conclusion Our data support an agreement between the heat fractionation and gel electrophoresis methods for the quantitative determination of liver and placental alkaline phosphatase isoenzymes. Although there is an association between the two methods, the activity of the bone isoenzyme was underestimated by the gel electrophoresis method, likely due to saturation of the gel and densitometry scan because of elevated protein concentrations. The non-liver fractions were qualitatively identified as intestinal isoenzyme.
5
Oliveira, Daria Pimenta de, Luiz Edson Mota de Oliveira, and Nelson Delú Filho. "Optimization of invertase assay conditions in rubber tree plants (Hevea brasiliensis Muell. Arg.)." Revista Árvore 30, no. 5 (October 2006): 687–92. http://dx.doi.org/10.1590/s0100-67622006000500001.
Full textAbstract:
The objective of this work was to define the optimal conditions for invertase assay, seeking to determine the ideal parameters for the different isoenzymes of leaf and bark tissues in adult rubber trees. Assays of varying pH, sucrose concentration and temperature of the reaction medium were conducted for the two investigated isoenzymes. The results pointed out the existence of two different pH related isoforms for the two analyzed tissues, with an isoenzyme being more active at pH 5,5 and the other at neutral/alkaline pH. Leaf blade isoenzymes presented similar values for substrate concentration, whereas the bark isoenzyme presented maximum values below those previously reported. The assays at different temperatures presented similar values for leaf isoenzymes, though they have differed significantly among the obtained values.
6
Giannoulaki, E. E., D. L. Kalpaxis, C. Tentas, and P. Fessas. "Lactate dehydrogenase isoenzyme pattern in sera of patients with malignant diseases." Clinical Chemistry 35, no. 3 (March 1, 1989): 396–99. http://dx.doi.org/10.1093/clinchem/35.3.396.
Full textAbstract:
Abstract Total lactate dehydrogenase (LDH; EC 1.1.1.27) activity and the percentage distribution of LDH isoenzymes were determined in 127 patients with malignant diseases. A shift in the isoenzyme patterns was observed toward the M-type, with an increase in the percentage of LDH-4 and LDH-5 isoenzymes and a slight increase in total LDH activity of all patients. Serum samples from 68 of the patients contained an abnormal isoenzyme of LDH, "LDH-1 ex," that, on agarose gel electrophoresis at pH 8.6, migrated between albumin and LDH-1 isoenzyme. Chemotherapy, radiotherapy, or surgical removal of the tumor was accompanied by disappearance of this abnormal isoenzyme. The heat stability of LDH-1 ex isoenzyme appears to be similar to that of LDH-1 but greater than that of the other LDH isoenzymes. Statistical analysis of these data demonstrated a significant correlation between malignancy and the appearance of LDH-1 ex isoenzyme (P less than 0.001). In contrast, the relationship between LDH-1 ex isoenzyme and metastasis or anatomical location of the malignancy is not statistically important (P less than 0.1).
7
BOWKER-KINLEY, Melissa M., I. Wilhelmina DAVIS, Pengfei WU, A. Robert HARRIS, and M. Kirill POPOV. "Evidence for existence of tissue-specific regulation of the mammalian pyruvate dehydrogenase complex." Biochemical Journal 329, no. 1 (January 1, 1998): 191–96. http://dx.doi.org/10.1042/bj3290191.
Full textAbstract:
Tissue distribution and kinetic parameters for the four isoenzymes of pyruvate dehydrogenase kinase (PDK1, PDK2, PDK3 and PDK4) identified thus far in mammals were analysed. It appeared that expression of these isoenzymes occurs in a tissue-specific manner. The mRNA for isoenzyme PDK1 was found almost exclusively in rat heart. The mRNA for PDK3 was most abundantly expressed in rat testis. The message for PDK2 was present in all tissues tested but the level was low in spleen and lung. The mRNA for PDK4 was predominantly expressed in skeletal muscle and heart. The specific activities of the isoenzymes varied 25-fold, from 50 nmol/min per mg for PDK2 to 1250 nmol/min per mg for PDK3. Apparent Ki values of the isoenzymes for the synthetic analogue of pyruvate, dichloroacetate, varied 40-fold, from 0.2 mM for PDK2 to 8 mM for PDK3. The isoenzymes were also different with respect to their ability to respond to NADH and NADH plus acetyl-CoA. NADH alone stimulated the activities of PDK1 and PDK2 by 20 and 30% respectively. NADH plus acetyl-CoA activated these isoenzymes nearly 200 and 300%. Under comparable conditions, isoenzyme PDK3 was almost completely unresponsive to NADH, and NADH plus acetyl-CoA caused inhibition rather than activation. Isoenzyme PDK4 was activated almost 2-fold by NADH, but NADH plus acetyl-CoA did not activate above the level seen with NADH alone. These results provide the first evidence that the unique tissue distribution and kinetic characteristics of the isoenzymes of PDK are among the major factors responsible for tissue-specific regulation of the pyruvate dehydrogenase complex activity.
8
Perrey, Ralf, Marie-Theres Hauser, and Michael Wink. "Cellular and Subcellular Localization of Peroxidase Isoenzymes in Plants and Cell Suspension Cultures from Lupinus polyphyllus." Zeitschrift für Naturforschung C 44, no. 11-12 (December 1, 1989): 931–36. http://dx.doi.org/10.1515/znc-1989-11-1210.
Full textAbstract:
Abstract , leaf protoplasts and cell suspension cultures of Lupinus polyphyllus and isolated vacuoles were studied for cellular and subcellular localization of peroxidase isoenzymes. Isoelectric focusing revealed 16 peroxidase isoenzymes. The basic peroxidase isoenzymes are predominantly localized in the vacuole and, to a minor degree, unbound in the intercellular space. The acidic isoenzymes are cell wall-bound in plants and not detectable in suspension-cultured cells. Large amounts (up to 11.0 U/ml) of a single basic isoenzyme are detectable in the spent medium of cell suspension cultures.
9
Bar, Jair, Stuart Spencer, Shethah Morgan, Laura Pike, David Cunningham, Jane D. Robertson, Juliane M. Jürgensmeier, and Glenwood D. Goss. "Correlation of lactate dehydrogenase (LDH) isoenzyme profile with outcome in advanced colorectal cancer (CRC) patients (pts) treated with chemotherapy and bevacizumab (BEV) or cediranib (CED)." Journal of Clinical Oncology 30, no. 15_suppl (May 20, 2012): e13541-e13541. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e13541.
Full textAbstract:
e13541 Background: There is a clinical need for predictive biomarkers of efficacy of VEGF signaling inhibitors (VSIs). LDH is a tetramer that can include any combination of the M and H subunits. LDH4 and 5 isoenzymes are composed mostly of the M subunit and are more abundant in hypoxic conditions. We speculated that the levels of LDH isoenzymes in pts serum may correlate with outcome of pts treated with VSIs. HORIZON I trial enrolled pts that were randomized to mFOLFOX6 with BEV or CED. A retrospective exploratory analysis was performed on baseline serum samples of these pts. Methods: Total serum LDH was tested on fresh samples during the conduct of the trial. About 2 years after the trial, frozen samples stored at -70 degrees were tested for total serum LDH and LDH isoenzymes, measured by agarose electrophoresis and a colorimetric enzymatic assay. Relative levels of M and H subunits were derived based on the known structure of each isoenzyme. Progression free survival (PFS) and overall survival (OS) were compared by subgroups of total LDH and LDH isoenzyme levels. P values were not calculated for these exploratory analyses. Results: Baseline total LDH levels from fresh serum were available for 207 pts. Total and isoenzyme LDH levels were available for frozen serum samples of 189 pts. Total LDH in the frozen and fresh samples correlated (R=0.9). Distant isoenzymes (e.g. LDH1 and 5) were negatively correlated. High M/H subunits ratio correlated with poor OS (HR=1.804, 95%CI 1.24-2.620). A non-significant trend for better OS to CED-treated vs. BEV-treated pts was seen in pts with high M/H ratio (e.g., CED 30mg vs BEV HR=0.685, 95%CI 0.382-1.23). Conclusions: Evaluation of LDH isoenzymes is feasible using serum samples kept frozen for 2 years. A negative correlation is seen between hypoxic-related and oxic-related isoenzymes. In CRC pts treated with a VSI, LDH isoenzyme hypoxia-associated profile correlates with poorer outcome. LDH isoenzyme profile as a possible predictive biomarker for benefit from CED vs. BEV requires further investigation.
10
Yoshikuni, Keiko, Takashi Matsuda, Janka Poracova, Akemi Sakai, Keiko Shimada, Noriko Tabuchi, and Kiyoh Tanishima. "Phylogenic Study of Denaturation of Lactate Dehydrogenase Isoenzymes from Different Species by High and Low Temperature." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 38, no. 5 (September 2001): 548–53. http://dx.doi.org/10.1177/000456320103800513.
Full textAbstract:
We studied the influence of storage at different temperatures on lactate dehydrogenase (EC 1.1.1.27; LD) isoenzymes from different tissues and different species, and analysed biochemical and biophysical mechanisms of denaturation during storage. Isoenzymes obtained from tissue extracts of mammals, poultry, reptiles, amphibians and fish were shown to have their own denaturation ranges at low temperatures by post-treatment assays and transition temperature analysis. These ranges were between − 10 and − 20°C for most vertebrate LD isoenzymes. Circular dichroism analysis indicated that the denaturation of LD isoenzymes was probably caused by a change in the hydrophobic interactions in the molecule. At higher temperatures, LD-1 isoenzyme was more thermostable than LD-5 from the same animal species, except for rats, the LD-5 activity of which was more thermostable than the LD-1 activity. These findings indicate that variable effects of storage of samples and reference materials at low temperatures should be considered, and that it is necessary to establish LD isoenzyme standards for animal clinical laboratory investigations.
11
Paavonen, T., K. Liippo, H. Aronen, and U. Kiistala. "Lactate dehydrogenase, creatine kinase, and their isoenzymes in pleural effusions." Clinical Chemistry 37, no. 11 (November 1, 1991): 1909–12. http://dx.doi.org/10.1093/clinchem/37.11.1909.
Full textAbstract:
Abstract Lactate dehydrogenase (LD; EC 1.1.1.27) and creatine kinase (CK; EC 2.7.3.2) are widely distributed cytoplasmic enzymes. LD has five and CK has three isoenzymes distributed in different proportions in various tissues. The amounts of LD and CK and the distribution of isoenzymes in different body fluids are not thoroughly characterized. We have measured the total LD and CK concentrations and their isoenzyme distribution in pleural aspirates and in serum from 22 patients with benign conditions and from 14 patients with malignant effusions. In malignant pleural fluid, the mean total LD was 662 U/L; in benign conditions, it was nearly 5840 U/L with large variations (91-43 400 U/L) according to clinical diagnosis, the highest values being reached in inflammatory lesions. The mean total CK concentration in pleural fluid was close to the serum value in both groups of patients, as was the pleural CK isoenzyme distribution. The LD isoenzyme distribution in pleural effusions differed from that in serum in both groups, with LD-4 and -5 being the main isoenzymes in their pleural fluid specimens (greater than 42% of total LD). The total LD concentration correlated somewhat (r = 0.57) with the total pleural protein content. In conclusion, the pleural LD isoenzyme distribution, both in benign and malignant conditions, differs from that in serum, having shifted towards more anaerobic and embryonic isoenzymes (LD-4 and -5). Moreover, the greater the concentration of pleural total LD, the greater the proportion of LD-4 and -5. These data suggest that visceral or parietal pleural cells are rich in LD isoenzymes 4 and 5.
12
Pompeu, Georgia Bertoni, Priscila Lupino Gratão, Victor Alexandre Vitorello, and Ricardo Antunes Azevedo. "Antioxidant isoenzyme responses to nickel-induced stress in tobacco cell suspension culture." Scientia Agricola 65, no. 5 (2008): 548–52. http://dx.doi.org/10.1590/s0103-90162008000500015.
Full textAbstract:
Exposure to nickel (Ni) at high concentrations can lead to production of reactive oxygen species (ROS) resulting in oxidative damage at the cellular level. We investigated the antioxidative responses of Nicotiana tabacum cv BY-2 cell suspension to Ni stress (0.075 and 0.75 mM NiCl2) over a 72 h period with special attention to potential alterations in isoenzymes of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR). Two main SOD isoenzymes were observed, a Mn-SOD (band I) and a Fe-SOD (band II), as well as one CAT isoenzyme and four GR isoenzymes. Activity staining analysis revealed that CAT activity plays a major role in the early response to Ni-induced oxidative stress, particularly when the Ni concentration used was low, whilst a specific GR isoenzyme appears to respond to the Ni-induced oxidative stress when a much higher Ni concentration was used to induce the stress for the same period of treatment. These results illustrate the importance and advantages of determining individual isoenzyme activities.
13
Tillyer, C. R., S. Rakhorst, and C. M. Colley. "Multicomponent analysis for alkaline phosphatase isoenzyme determination by multiple linear regression." Clinical Chemistry 40, no. 5 (May 1, 1994): 803–10. http://dx.doi.org/10.1093/clinchem/40.5.803.
Full textAbstract:
Abstract Alkaline phosphatase (EC 3.1.3.1) isoenzymes in serum may be determined by multicomponent analysis of the enzyme activities in the presence of multiple inhibitors. To determine inhibition coefficients of the isoenzymes, we used multiple linear regression analysis to compare alkaline phosphatase activities in the presence of known inhibitors with electrophoretically determined isoenzyme activities in plasma and serum samples. All possible combinations of exactly determined and overdetermined linear systems of inhibitors were ranked according to their prediction error to select an optimum set. The best multicomponent system for prediction included the use of levamisole, phenylalanine, and heat inhibition at 56 degrees C and 65 degrees C to determine bone, hepatic, intestinal, and placental isoenzymes. Consideration of the hepatic isoenzyme as liver and macromolecular fractions resulted in significantly worse predictions. Error analysis involving repeat determinations and a simplex optimization of the inhibition coefficients indicated that the inaccuracy of the comparison electrophoretic method may have been a major factor affecting poor isoenzyme prediction in some samples.
14
Vora, S., R. Oskam, and G. E. Staal. "Isoenzymes of phosphofructokinase in the rat. Demonstration of the three non-identical subunits by biochemical, immunochemical and kinetic studies." Biochemical Journal 229, no. 2 (July 15, 1985): 333–41. http://dx.doi.org/10.1042/bj2290333.
Full textAbstract:
In man and the rabbit, 6-phosphofructokinase (PFK, EC 2.7.1.11) exists in tetrameric isoenzymic forms composed of muscle (M or A), liver (L or B) and platelet or brain (P or C) subunits, which are under separate genetic control. In contrast, the genetic control of the rat PFK has not yet been conclusively established; it is unclear whether the P-type or C-type subunit exists in this species. To resolve this question, we investigated the enzyme from the skeletal muscle, liver and brain of rats of Wag/Rij strain. Our studies demonstrate that the rat PFK is also under the control of three structural loci and that the homotetramers M4, P4 and L4 exhibit unique chromatographic, immunological and kinetic-regulatory properties. Skeletal-muscle and brain PFKs consist of isolated M4 and P4 homotetramers respectively. Although liver PFK consists predominantly of L4 homotetramer, it also contains small amounts of PL3 and P2L2 species. All three PFKs exhibit allosteric properties: co-operativity with fructose 6-phosphate and inhibition by ATP decrease in the order P4 greater than L4 greater than M4. P4 and M4 tetramers are the most sensitive to citrate inhibition, whereas L4 tetramer is the least sensitive. More importantly, P4 and L4 isoenzymes are the most sensitive to activation by fructose 2,6-bisphosphate, whereas M4 isoenzyme is the least sensitive. These results indicate that the brain PFK in this strain of rat is a unique tetramer, P4, which also exhibits allosteric kinetics, as do the well-studied M4 and L4 isoenzymes. The reported differences in the number and nature of isoenzymes present in the rat brain and liver most probably reflect the differences in the strains studied by previous investigators. Since the nature of the rat PFK isoenzymes and nomenclatures reported by previous investigators have been now reconciled, it is proposed that, for the sake of uniformity, only well-established nomenclatures used for the rabbit or human PFK isoenzymes be used for the rat isoenzymes.
15
Journal, Baghdad Science. "Kinetic studies of AST isoenzymes I,II,III,IV partially purified from patient,s urine with chroinc renal failure." Baghdad Science Journal 7, no. 1 (March 7, 2010): 437–43. http://dx.doi.org/10.21123/bsj.7.1.437-443.
Full textAbstract:
In this research, the kinetic studies of four isoenzymes of Asprtate aminotransferase, which partially purified from the urine of chronic renal failure patients were carried out .The four isoenzymes were obeyed Michaelis-Menton's equation and the optimum concentration of their substrate (Aspartic acid) was (166.5x10-3) mole/liter,and their Km values were determined. Four isoenzymesI,II,III,IV have shown an optimum pH at 7.4.The four isoenzymes obeyed Arrhenius equation up to 37º C and their Ea and Q10 constants were determined .
16
Schoenau, E., K. H. Herzog, and H. J. Boehles. ""Fragmented" isoenzymes of alkaline phosphatase in the diagnosis of transient hyperphosphatasemia." Clinical Chemistry 32, no. 12 (December 1, 1986): 2211–13. http://dx.doi.org/10.1093/clinchem/32.12.2211.
Full textAbstract:
Abstract We describe the appearance of "fragmented" isoenzymes of serum alkaline phosphatase (EC 3.1.3.1) in two cases of transient hyperphosphatasemia. We determined the isoenzymes by liquid chromatography, then characterized them by heat inactivation, inhibition with 5 mmol/L L-phenylalanine solution, and electrophoresis on cellulose acetate membranes. We suspect that a virus-induced decrease in clearance of the enzyme from serum is responsible for a similar increase of bone and liver isoenzyme activities and for the presence of these fragmented isoenzymes in transient hyperphosphatasemia.
17
Mattiazzo, M., and I. Ramasamy. "Wheat germ lectin affinity electrophoresis of serum alkaline phosphatase with commercially available agarose gels." Clinical Chemistry 39, no. 7 (July 1, 1993): 1404–7. http://dx.doi.org/10.1093/clinchem/39.7.1404.
Full textAbstract:
Abstract We have modified a commercially available procedure involving precast agarose gels (Paragon Isopal System) to measure alkaline phosphatase (EC 3.1.3.1) isoenzymes. Including wheat germ lectin in the equilibration buffer improved the resolution of the bone and liver isoenzymes. Unlike previously described wheat germ lectin affinity electrophoresis methods, the procedure measures bone, liver, and biliary isoenzymes in a single step. There was good correlation between the affinity electrophoresis and the neuraminidase preincubation methods for the measurement of bone (r = 0.958) and liver (r = 0.962) alkaline phosphatase isoenzymes. However, the affinity electrophoresis method also quantified minor isoenzyme fractions that were poorly resolved by the neuraminidase method. The method is technically simple, reproducible, and capable of rapid handling of large workloads.
18
Severini, G., L. M. Aliberti, and M. Di Girolamo. "N-acetyl-beta-glucosaminidase isoenzymes in serum and urine of patients with diabetes mellitus." Clinical Chemistry 34, no. 12 (December 1, 1988): 2430–32. http://dx.doi.org/10.1093/clinchem/34.12.2430.
Full textAbstract:
Abstract The isoenzyme pattern of N-acetyl-beta-glucosaminidase (NAG) in serum and urine was studied in two groups of patients with diabetes mellitus and in 30 control subjects. Total NAG activity was significantly (P less than 0.001) increased in the serum and urine of the 20 diabetics with vascular complications, but was insignificantly increased in the 20 diabetics without vascular complications. Ion-exchange chromatography demonstrated the presence of two major isoenzymes of NAG, A and B. The proportion of isoenzyme A activity always exceeded that of isoenzyme B. The proportion of isoenzyme B in serum of diabetics was lower than in controls; the reverse was true for urine of diabetics. The NAG isoenzymes pattern may provide additional diagnostic information regarding diabetic status and complications of diabetes.
19
Kaldis, P., M. Stolz, M. Wyss, E. Zanolla, B. Rothen-Rutishauser, T. Vorherr, and T. Wallimann. "Identification of two distinctly localized mitochondrial creatine kinase isoenzymes in spermatozoa." Journal of Cell Science 109, no. 8 (August 1, 1996): 2079–88. http://dx.doi.org/10.1242/jcs.109.8.2079.
Full textAbstract:
The creatine kinase (CK) isoenzyme system is essential for motility in rooster and sea urchin sperm. In the present study, biochemical characterization as well as immunofluorescence and confocal laser microscopy with highly specific antibodies against various chicken CK isoenzymes revealed that cytosolic brain-type CK isoenzyme (B-CK) is the only CK isoenzyme in rooster seminal plasma, while three isoenzymes, cytosolic B-CK, sarcomeric mitochondrial CK (Mib-CK), and a variant of ubiquitous Mi-CK (‘Mia-CK variant’), are found in rooster spermatozoa. These three isoenzymes are localized in different regions of the sperm cell. B-CK and Mib-CK were localized along the entire sperm tail and in the mitochondria-rich midpiece, respectively. The ‘Mia-CK variant’, on the other hand, was found predominantly at the head-midpiece boundary, in a non-uniform manner in the midpiece itself and, surprisingly, at the distal end of the sperm tail as well as at the acrosome. Several lines of evidence show that the ‘Mia-CK variant’ shares some characteristics with purified Mia-CK from chicken brain, but also displays distinctive features. This is the first evidence for two different Mi-CK isoenzymes occurring in one cell and, additionally, for the co-expression of Mib-CK and cytosolic brain-type B-CK in the same cell. The relevance of these findings for sperm physiology and energetics is discussed.
20
Segil, N., A. Shrutkowski, M. B. Dworkin, and E. Dworkin-Rastl. "Enolase isoenzymes in adult and developing Xenopus laevis and characterization of a cloned enolase sequence." Biochemical Journal 251, no. 1 (April 1, 1988): 31–39. http://dx.doi.org/10.1042/bj2510031.
Full textAbstract:
As part of a study of glycolysis during early development we have examined the pattern of expression of enolase isoenzymes in Xenopus laevis. In addition, the nucleotide sequence of a cDNA clone coding for the complete amino acid sequence of one enolase gene (ENO1) in X. laevis was determined. X. laevis ENO1 shows highest homology to mammalian non-neuronal enolase. Analysis of enolase isoenzymes in X. laevis by non-denaturing electrophoresis on cellulose acetate strips revealed five isoenzymes. One form was present in all tissues tested, two additional forms were expressed in oocytes, embryos, adult liver and adult brain, and two further forms were restricted to larval and adult muscle. Since enolase is a dimer, three different monomers (gene products) could account for the observed number of isoenzymes. This pattern of enolase isoenzyme expression in X. laevis differs from that of birds and mammals. In birds and mammals the most acidic form is neuron-specific and there is only one major isoenzyme expressed in the liver. RNAase protection experiments showed the presence of ENO1 mRNA in oocytes, liver and muscle, suggesting that it codes for a non-tissue-restricted isoenzyme. ENO1 mRNA concentrations are high in early oocytes, decrease during oogenesis and decrease further after fertilization. Enolase protein, however, is maintained at high concentrations throughout this period.
21
Ojopagogo, Yetunde Adedolapo, and Isaac Olusanjo Adewale. "Alteration in the status of glutathione transferase of the water snail, Bulinus globosus, during aestivation and recovery." Animal Biology 60, no. 2 (2010): 145–55. http://dx.doi.org/10.1163/157075610x491680.
Full textAbstract:
AbstractThe varying status of glutathione transferases (GSTs) in water snail, Bulinus globosus, an intermediate host of disease-causing Schistosoma haematobium (Bilharz 1852) has been investigated. The expression of GST isoenzymes in the water snail appears seasonal with about three isoenzymes appearing during raining season, when the organism is active, which may reduce to a single peak of one isoenzyme during aestivation, when the organism is inactive. GST isoenzyme is present in high concentration in all the tissues investigated namely: haemolymph, foot muscle and hepatopancreas with specific activities of 0.006 ± 0.002, 0.45 ± 0.021 and 1.33 ± 0.103 units/mg protein respectively for 1-chloro-2,4-dinitrobenzene (CDNB) as substrate. With this substrate, the specific activity of GST from the hepatopancreas appears higher than the specific activities that have been previously reported for GSTs from molluscs. Partial purification of the isoenzymes using Tris acrylic acid-based resins enabled us to observe that GST appears to be the major protein in the hepatopancreas of this organism. We also found indications for the presence of an endogenous GST inhibitor in the cytosol, whose function is yet unknown. All the traditional GST inhibitors such as cibacron blue, hematin, bromosulfophthalein and S-hexylglutathione were able to inhibit the isoenzymes effectively, with cibacron blue being the most potent. The isoenzymes however have narrow substrate specificity. We conclude that different isoenzymes of GST are expressed in the same class of molluscs, even when they belong to the same genus or species, and that the expression may depend on whether the snails are on aestivation or not.
22
Salas, C., S. Lobos, J. Larrain, L. Salas, D. Cullen, and R. Vicuna. "Properties of laccase isoenzymes produced by the basidiomycete Ceriporiopsis subvermispora." Biotechnology and Applied Biochemistry 21, no. 3 (June 1995): 323–33. http://dx.doi.org/10.1111/j.1470-8744.1995.tb00338.x.
Full textAbstract:
Laccase is one of the ligninolytic enzymes found in liquid cultures of the fungus Ceriporiopsis subvermispora in defined medium. As an approach to a clarification of the role of laccases during the attack on lignin by the fungus, the enzyme has been characterized further. The levels of this phenol oxidase increase 2‐fold in the presence of p‐anisidine and are severely affected when addition of either Mn(II) or Cu(II) ions to the medium is omitted. Isoelectrofocusing allowed the resolution of two laccase isoenzymes, with pIs of 3.65 and 3.59. In rich medium, laccase activity is 10‐fold higher than in salt medium, and it is not affected by the external addition of p‐anisidine or Mn(II). Four isoenzymes were detected in these cultures, with pIs between 3.76 and 3.60. In a wheat bran medium, four isoenzymes with pIs in the range 3.63‐3.46, plus a fifth isoenzyme of high pI (4.82), were also identified. The absorption spectrum of a pool containing the four isoenzymes from rich medium shows a maximum at 600 nm, typical of laccase possessing a type I copper atom. The molecular mass of the isoenzyme with pI 3.60 is 79 kDa, as determined by SDS/PAGE. Upon treatment with endoglycosidase F, the molecular mass of this isoform decreases to 63 kDa, indicating a high degree of glycosylation. Substrate specificity studies conducted with the four isoenzymes from rich medium and a combination of isoenzymes from salt medium showed marked differences among them. The amino‐terminal sequences (24 residues) of three isoenzymes isolated from rich medium were determined. Two of them are identical, whereas the third one differs from these in three amino acid residues. The consensus sequence reveals clear homology with laccases from other microorganisms.
23
Abbott, L. B., and F. Van Lente. "Procedure for characterization of creatine kinase variants on agarose electrophoretograms." Clinical Chemistry 31, no. 3 (March 1, 1985): 445–47. http://dx.doi.org/10.1093/clinchem/31.3.445.
Full textAbstract:
Abstract Electrophoretograms of atypical creatine kinase (EC 2.7.3.2, CK) isoenzymes may be difficult to interpret. In addition, their presence may cause discrepancies between results by immunological determinations for mass or activity and those by electrophoresis. Here we outline procedures to use in characterizing apparently atypical CK isoenzymes observed after electrophoresis, as illustrated by a CK isoenzyme variant that migrated as CK-MB.
24
Connor, K., and R. A. Clegg. "Isoenzymes of protein kinase C in rat mammary tissue: changes in properties and relative amounts during pregnancy and lactation." Biochemical Journal 291, no. 3 (May 1, 1993): 817–24. http://dx.doi.org/10.1042/bj2910817.
Full textAbstract:
Protein kinase isoenzymes belonging to the protein kinase C (PK-C) family present in rat mammary tissue have been resolved from one another by chromatography on hydroxyapatite, and characterized. PK-C alpha is the predominant isoenzyme and is present at a constant level of activity throughout mammary-gland development and differentiation. In contrast, marked changes in the relative abundance of other mammary PK-C isoenzymes accompany the transition from pregnancy to lactation. The sensitivity of mammary PK-C alpha to Ca2+ is greater in tissue from pregnant than from lactating rats. This isoenzyme has other atypical properties consistent with its being more highly phosphorylated than PK-C alpha in rat brain and spleen. One of the protein kinase isoenzymes resolved from mammary tissue recognizes the peptide substrate used to assay AMP-activated kinase and may thus interfere in the determination of this activity. Another is fully active in the absence of Ca2+ and is more than 80% active in the absence of added lipid effectors. A ‘housekeeping’ role is proposed for PK-C alpha in mammary tissue, whereas the less abundant PK-C isoenzymes may be involved in mammary cell proliferation and differentiation.
25
Delporte, C., P. Poloczek, and J. Winand. "Role of phosphodiesterase II in cross talk between cGMP and cAMP in human neuroblastoma NB-OK-1 cells." American Journal of Physiology-Cell Physiology 270, no. 1 (January 1, 1996): C286—C292. http://dx.doi.org/10.1152/ajpcell.1996.270.1.c286.
Full textAbstract:
Cyclic nucleotides levels and cyclic nucleotide phosphodiesterase (PDE) activities were measured in human neuroblastoma NB-OK-1 cells possessing atrial natriuretic peptide (ANP) receptors of the A type and pituitary adenylate cyclase activating polypeptide (PACAP)-preferring receptors. Adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) degradation were interrelated since the increase in cGMP, induced by ANP-(99-126), stimulated the hydrolysis of cAMP by PDE isoenzyme II. In intact NB-OK-1 cells, the levels of cAMP and cGMP attained in the presence of, respectively, 1 nM PACAP-(1-27) and 10 nM ANP-(99-126), and in the absence or presence of PDE inhibitors, strongly suggested that cAMP hydrolysis was mainly achieved by isoenzyme IV, and to a lesser extent by isoenzymes I, II, and III, while cGMP was degraded by isoenzymes I, II, III, and V. More than one-half of total cAMP- and cGMP-hydrolyzing activities was present in the membrane-bound fraction. Cyclic nucleotide PDE activities separated by anion-exchange chromatography showed that isoenzymes III and IV were mainly present in the membrane fraction, while isoenzymes I, II, and V were in the cytosolic fraction.
26
Jaffe, A. S., Y. Landt, C. A. Parvin, D. R. Abendschein, E. M. Geltman, and J. H. Ladenson. "Comparative sensitivity of cardiac troponin I and lactate dehydrogenase isoenzymes for diagnosing acute myocardial infarction." Clinical Chemistry 42, no. 11 (November 1, 1996): 1770–76. http://dx.doi.org/10.1093/clinchem/42.11.1770.
Full textAbstract:
Abstract Criteria for the retrospective diagnosis of acute myocardial infarction rely heavily on increases in lactate dehydrogenase (LD) isoenzymes. However, increases of LD isoenzyme activities are not specific for myocardial injury. Recently, increased concentrations of cardiac troponin I (cTnI) have been shown to be highly specific for myocardial damage and to have sensitivity comparable with that of creatine kinase MB isoenzyme for detecting cardiac injury. Furthermore, increases of cTnI persist in plasma for at least several days. The present study was designed to determine the relative sensitivities of cTnI and LD isoenzymes over time for the diagnosis of infarction. The results indicate that cTnI values are at least as sensitive as LD isoenzymes: 90% of patients with myocardial infarction had above-normal concentrations of cTnI on the 4th day after admission to the coronary care unit. Criteria based on cTnI should improve the accuracy of retrospective diagnoses of acute myocardial infarction.
27
Singh, S. V., T. Leal, G. A. Ansari, and Y. C. Awasthi. "Purification and characterization of glutathione S-transferases of human kidney." Biochemical Journal 246, no. 1 (August 15, 1987): 179–86. http://dx.doi.org/10.1042/bj2460179.
Full textAbstract:
Several forms of glutathione S-transferase (GST) are present in human kidney, and the overall isoenzyme pattern of kidney differs significantly from those of other human tissues. All the three major classes of GST isoenzymes (α, mu and pi) are present in significant amounts in kidney, indicating that GST1, GST2 and GST3 gene loci are expressed in this tissue. More than one form of GST is present in each of these classes of enzymes, and individual variations are observed for these classes. The structural, immunological and functional properties of GST isoenzymes of three classes differ significantly from each other, whereas the isoenzymes belonging to the same class have similar properties. All the cationic GST isoenzymes of human kidney except for GST 9.1 are heterodimers of 26,500-Mr and 24,500-Mr subunits. GST 9.1 is a dimer of 24,500-Mr subunits. All the cationic isoenzymes of kidney GST cross-react with antibodies raised against a mixture of GST α, beta, gamma, delta and epsilon isoenzymes of liver. GST 6.6 and GST 5.5 of kidney are dimers of 26,500-Mr subunits and are immunologically similar to GST psi of liver. Unlike other human tissues, kidney has at least two isoenzymes (pI 4.7 and 4.9) associated with the GST3 locus. Both these isoenzymes are dimers of 22,500-Mr subunits and are immunologically similar to GST pi of placenta. Some of the isoenzymes of kidney do not correspond to known GST isoenzymes from other human tissues and may be specific to this tissue.
28
Dunaway, G. A., T. P. Kasten, T. Sebo, and R. Trapp. "Analysis of the phosphofructokinase subunits and isoenzymes in human tissues." Biochemical Journal 251, no. 3 (May 1, 1988): 677–83. http://dx.doi.org/10.1042/bj2510677.
Full textAbstract:
The 6-phosphofructo-1-kinase (PFK) subunits and isoenzymes were studied in human muscle, heart, brain, liver, platelets, fibroblasts, erythrocytes, placenta and umbilical cord. In each tissue, the subunit types in the native isoenzymes were characterized by immunological titration with subunit-specific antibodies and by column chromatography on QAE (quaternary aminoethyl)-Sephadex. Further, the subunits of the partially purified native isoenzymes were resolved by SDS/polyacrylamide-gel electrophoresis, identified by immunoblotting, and quantified by scanning gel densitometry of silver-stained gels and immunoblots. Depending on the type of tissue, one to three subunits were detected. The Mr values of the L, M and C subunits regardless of tissue were 76,700 +/- 1400, 82,500 +/- 1640 and 86,500 +/- 1620. Of the tissues studied, only the muscle PFK isoenzymes exhibited one subunit, which was the M-type subunit. Of the other tissues studied, the PFK isoenzymes contained various amounts of all three subunits. Considering the properties of the native PFK isoenzymes, it is clear that, in human tissues, they are not simply various combinations of two or three homotetrameric isoenzymes, but complex mixtures of homotetramers and heterotetramers. The kinetic/regulatory properties of the various isoenzyme pools were found to be dependent on subunit composition.
29
DUJARDIN, J. C., A. L. BAÑULS, J. P. DUJARDIN, J. AREVALO, M. TIBAYRENC, and D. LE RAY. "Comparison of chromosome and isoenzyme polymorphism in geographical populations of Leishmania (Viannia) peruviana." Parasitology 117, no. 6 (December 1998): 547–54. http://dx.doi.org/10.1017/s0031182098003357.
Full textAbstract:
Five chromosomes and 17 isoenzyme loci were analysed in 4 allopatric populations of Leishmania (Viannia) peruviana, and molecular distances calculated with 2 estimators, Chromosomal Size Difference Index and Jaccard Distance. Chromosome and isoenzyme data were in overall concordance: 13/30 isolates clustered similarly on the dendrograms constructed from the different estimators, and a significant correlation (P<0·001) was observed between the molecular distances calculated from the two sets of characters. This indicates an evolutionary association between chromosomal size polymorphism and isoenzymes. Chromosomes have a faster molecular clock than isoenzymes; twice as many genotypes were identified by chromosome analysis and significant size differences (for a total of up to 500 kb for 5 chromosomes together) were observed within a given zymodeme. Chromosomes most likely represent better indicators of genetic drift than isoenzymes, as suggested by the higher correlation between both estimators of chromosomal size-polymorphism and eco-geography. Some chromosomes might present an adaptive response to environmental variation.
30
Maekawa, M., K. Sudo, K. Iwahara, and T. Kanno. "Lactate dehydrogenase inhibition by immunoglobulin G in human serum." Clinical Chemistry 32, no. 7 (July 1, 1986): 1347–49. http://dx.doi.org/10.1093/clinchem/32.7.1347.
Full textAbstract:
Abstract Low lactate dehydrogenase (LD; EC 1.1.1.27) activity and an abnormal LD pattern in electrophoretograms of LD isoenzymes in the sera of two patients were caused by inhibition of LD by immunoglobulin G. One of these showed inhibitor activity in the serum upon direct analysis, while the other showed activity only after the immunoglobulin was stripped from the LD. As judged from the LD isoenzyme patterns in serum, the LD inhibitor appeared to act against M subunits. However, quantification of binding affinities to each isolated isoenzyme showed that the LD inhibitor had a stronger effect on LD isoenzymes 2 and 3 (H3M1 and H2M2, respectively).
31
Viallard, J. L., D. Caillaud, and B. Kantelip. "Atypical enolase isoenzyme in serum: a macroenolase formed from the alpha gamma-hybrid form." Clinical Chemistry 36, no. 11 (November 1, 1990): 2000–2003. http://dx.doi.org/10.1093/clinchem/36.11.2000.
Full textAbstract:
Abstract We report an abnormal pattern for enolase (EC 4.2.1.11) isoenzymes in the serum of a patient with squamous cell lung carcinoma. The alpha alpha-isoenzyme was present but the alpha gamma form was not detected, and near the point of application on the electrophoretogram was an abnormal band. We determined that the abnormal fraction corresponded to a macroenolase, composed of the alpha gamma-isoenzyme complexed with IgG. From a practical point of view, the presence of such a macroenolase, containing gamma-subunits, results in falsely increased results for neuron-specific enolase (NSE) in procedures that determine only the NSE concentration without consideration of the enolase isoenzymes.
32
Niblock, A. E., G. Jablonsky, F. Y. Leung, and A. R. Henderson. "Changes in mass and catalytic activity concentrations of aspartate aminotransferase isoenzymes in serum after a myocardial infarction." Clinical Chemistry 32, no. 3 (March 1, 1986): 496–500. http://dx.doi.org/10.1093/clinchem/32.3.496.
Full textAbstract:
Abstract We used an RIA and inhibition of enzyme activity to monitor the changes in mass and catalytic concentrations of the aspartate aminotransferase (EC 2.6.1.1;AST) isoenzymes in serum after myocardial infarction. Cytosolic (c-AST) and mitochondrial (m-AST) forms of AST were present in sera from all 38 of our patients. Although the immunological and catalytic concentrations of both isoenzymes correlated well with the size of the infarct, c-AST gave a better measure than did m-AST. About 20% of the total enzyme activity at peak activity was from the mitochondrial isoenzyme. Both isoenzyme activities peak at very nearly the same time, but m-AST has the longer half-life. Immunological evidence of the mitochondrial isoenzyme can be detected in serum for at least eight days after the infarct. The presence of left ventricular failure produces greater serum isoenzyme activities than in those without failure.
33
Root, C. F., J. S. Fine, and K. J. Clayson. "Isoelectric focusing of neuraminidase-treated alkaline phosphatase isoenzymes on agarose gel." Clinical Chemistry 33, no. 6 (June 1, 1987): 830–32. http://dx.doi.org/10.1093/clinchem/33.6.830.
Full textAbstract:
Abstract We attempted to separate bone and liver alkaline phosphatase (EC 3.1.3.1) isoenzymes in human serum by isoelectric focusing on agarose gel. We found that in a pH 3-10 gradient the liver and bone isoenzymes focused into so many bands over a narrow pH range such that the information could not be quantified. However, when the bone isoenzyme in serum was first desialylated at 37 degrees C for a minimum of 6 h, catalyzed by neuraminidase (EC 3.2.1.18) at pH 5.8-6.0, we could detect four distinct bands with pls of 6.7, 6.8, 6.9, and 7.0. Under the same conditions, the liver isoenzyme in human serum focused into one band at pH 7.0. The multiple banding we observed for the desialylated bone isoenzyme has not been previously reported. The method is suited as a qualitative technique for detecting the bone alkaline phosphatase isoenzyme in serum.
34
Shibasaki, T., H. Gomi, F. Ishimoto, and T. Miyahara. "Urinary N-acetyl-beta-D-glucosaminidase isoenzyme activity as measured by fast protein liquid chromatography in patients with nephrotic syndrome." Clinical Chemistry 36, no. 1 (January 1, 1990): 102–3. http://dx.doi.org/10.1093/clinchem/36.1.102.
Full textAbstract:
Abstract Exactly why N-acetyl-beta-D-glucosaminidase (NAG) excretion is increased in patients with nephrotic syndrome with glomerular lesions is poorly understood. Glomeruli contain less NAG than do proximal tubules. In this study, we have tried to measure the NAG isoenzymes automatically by use of the recently developed fast protein liquid chromatography (FPLC) system, followed by column chromatography on DEAE cellulose (Mono Q). Three isoenzyme peaks--B, I + II, and A--were observed for urine from both healthy subjects and nephrotic patients. The B isoenzyme usually constituted about 10% of the total NAG in healthy controls, 30% in nephrotic patients. In contrast, the proportion of the A isoenzyme was inversely related to that of the B isoenzyme when healthy controls and nephrotic patients were compared. Our system for measuring NAG isoenzymes is reproducible and fast, and it should be useful in further studies.
35
Palmieri, Gianna, Paola Giardina, Carmen Bianco, Bianca Fontanella, and Giovanni Sannia. "Copper Induction of Laccase Isoenzymes in the Ligninolytic Fungus Pleurotus ostreatus." Applied and Environmental Microbiology 66, no. 3 (March 1, 2000): 920–24. http://dx.doi.org/10.1128/aem.66.3.920-924.2000.
Full textAbstract:
ABSTRACT Pleurotus ostreatus is a white rot basidiomycete that produces several extracellular laccase isoenzymes, including phenol oxidase A1b (POXA1b), POXA2, and POXC. POXC was the most abundant isoenzyme produced under all of the growth conditions examined in this study. Copper was the most efficient inducer of laccase activity among the putative inducers tested. The amounts of all of the previously described laccase isoenzymes increased substantially in copper-supplemented cultures. Under these conditions expression of POX isoenzymes was regulated at the level of gene transcription. It is worth noting that poxa1b mRNA was the most abundant induced transcript at all of the growth times analyzed, and the amount of this mRNA increased until day 7. The discrepancy between thepoxa1b transcript and protein amounts can be explained by the presence of a high level of the protein in P. ostreatuscellular extract, which indicated that the POXA1b isoenzyme could be inefficiently secreted and/or that its physiological activity could occur inside the cell or on the cell wall. Moreover, the POXA1b isoenzyme behaved uniquely, as its activity was maximal on the second day of growth and then decreased. An analysis performed with protease inhibitors revealed that the loss of extracellular POXA1b activity could have been due to the presence of specific proteases secreted into the copper-containing culture medium that affected the extracellular POXA1b isoenzyme.
36
Bourtzis, K., and V. J. Marmaras. "Integumental phosphatase isoenzymes from white puparia of Ceratitis capitata: isolation and characterization." Biochemistry and Cell Biology 69, no. 10-11 (October 1, 1991): 731–35. http://dx.doi.org/10.1139/o91-110.
Full textAbstract:
Two specific alkaline phosphatase forms were identified in the integument of wild-type Ceratitis capitata during transition of larvae to pupae. The separation was achieved by DEAE-cellulose chromatography; alkaline phosphatase 1 and alkaline phosphatase 2 were eluted in 0.1 and 0.4 M KC1, respectively. Both isoenzymes have a molecular weight of approximately 180 000. The pH curve reveals two peaks for both alkaline phosphatases: one at 9.4 and the other at 11.0. The two isoenzymes at both pH optima catalyze the hydrolysis of phosphotyrosine and β-glycerophosphate, but not phosphoserine, phosphothreonine, ATP, or AMP. However, at pH 9.4, alkaline phosphatase 1 is more effective than ALPase 2 and exhibits a preference for phosphotyrosine. The divalent cations Mn2+, Mg2+, and Ba2+ activate the enzymes, while Cu2+ and Zn2+ are inhibitors for both isoenzymes. Both isoenzymes are inactivated by EDTA. The effect of amino acids on enzyme activity was also tested. Alkaline phosphatase 1 is inhibited by L-tyrosine, while alkaline phosphatase 2 is unaffected. L-Phenylalanine has no effect on either isoenzyme. Both isoenzymes are inhibited by urea and 2-mercaptoethanol. Simultaneous addition of urea and 2-mercaptoethanol reveals that ALPase 1 is more sensitive to these inhibitors than ALPase 2.Key words: enzyme, Diptera, integument, phosphatase, isoenzymes, phosphotyrosine.
37
Doyle, J. M., M. E. Schininà, F. Bossa, and S. Doonan. "The amino acid sequence of cytosolic aspartate aminotransferase from human liver." Biochemical Journal 270, no. 3 (September 15, 1990): 651–57. http://dx.doi.org/10.1042/bj2700651.
Full textAbstract:
1. The cytosolic aspartate aminotransferase was purified from human liver. 2. The isoenzyme contains four cysteine residues, only one of which reacts with 5,5′-dithiobis-(2-nitrobenzoic acid) in the absence of denaturing agents. 3. The amino acid sequence of the isoenzyme is reported, as determined from peptides produced by digestion with trypsin and with CNBr, and from sub-digestion of some of these peptides with Staphylococcus aureus V8 proteinase. 4. The isoenzyme shares 48% identity of amino acid sequence with the mitochondrial form from human heart. 5. Comparisons of the amino acid sequences of all known mammalian cytosolic aspartate aminotransferases and of the same set of mitochondrial isoenzymes are reported. The results indicate that the cytosolic isoenzymes have evolved at about 1.3 times the rate of the mitochondrial forms. 6. The time elapsed since the cytosolic and mitochondrial isoenzymes diverged from a common ancestral protein is estimated to be 860 x 10(6) years. 7. Experimental details and confirmatory data for the results presented here are given in a supplementary paper that has been deposited as a Supplementary Publication SUP 50158 (25 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1990) 265, 5.
38
Hirata, R. D., M. H. Hirata, B. Strufaldi, R. A. Possik, and M. Asai. "Creatine kinase and lactate dehydrogenase isoenzymes in serum and tissues of patients with stomach adenocarcinoma." Clinical Chemistry 35, no. 7 (July 1, 1989): 1385–89. http://dx.doi.org/10.1093/clinchem/35.7.1385.
Full textAbstract:
Abstract Total activities of creatine kinase (EC 2.7.3.2; CK) and lactate dehydrogenase (EC 1.1.1.27; LD) and their isoenzymes were estimated in serum and tissue samples from patients with stomach adenocarcinomas who were to undergo gastric resection. Total CK activity (U/g protein) appeared to be markedly decreased in neoplastic stomach tissue. CK-BB was the predominant isoenzyme in both neoplastic and normal stomach tissues; however, the CK-BB/total CK ratio was increased in adenocarcinoma tissue. Macro CK type 1 was found in two neoplastic tissues and macro CK type 2 in 11. LD4 and LD5 isoenzymes were predominant in gastric tissues, but LD5 and the LD5/LD1 ratio were higher in adenocarcinoma tissue. At 24 h before surgery, CK-BB was demonstrated in sera of all patients and CK-MB in 69%. The CK-BB probably originated from neoplastic stomach tissue, which contains high CK activity, with BB isoenzyme predominating. After gastrectomy, CK and LD isoenzymes in sera were markedly increased by 24 h postsurgery. These alterations were attributed to release from damaged tissue during gastric resection.
39
TUGANOVA, Alina, Igor BOULATNIKOV, and Kirill M. POPOV. "Interaction between the individual isoenzymes of pyruvate dehydrogenase kinase and the inner lipoyl-bearing domain of transacetylase component of pyruvate dehydrogenase complex." Biochemical Journal 366, no. 1 (August 15, 2002): 129–36. http://dx.doi.org/10.1042/bj20020301.
Full textAbstract:
Protein—protein interactions play an important role in the regulation of enzymic activity of pyruvate dehydrogenase kinase (PDK). It is generally believed that the binding of PDK to the inner lipoyl-bearing domain L2 of the transacetylase component E2 of pyruvate dehydrogenase complex largely determines the level of kinase activity. In the present study, we characterized the interaction between the individual isoenzymes of PDK (PDK1—PDK4) and monomeric L2 domain of human E2, as well as the effect of this interaction on kinase activity. It was found that PDK isoenzymes are markedly different with respect to their affinities for L2. PDK3 demonstrated a very tight binding, which persisted during isolation of PDK3—L2 complexes using size-exclusion chromatography. Binding of PDK1 and PDK2 was readily reversible with the apparent dissociation constant of approx. 10μM for both isoenzymes. PDK4 had a greatly reduced capacity for L2 binding (relative order PDK3>PDK1 = PDK2>PDK4). Monomeric L2 domain alone had very little effect on the activities of either PDK1 or PDK2. In contrast, L2 caused a 3-fold increase in PDK3 activity and approx. 37% increase in PDK4 activity. These results strongly suggest that the interactions between the individual isoenzymes of PDK and L2 domain are isoenzyme-specific and might be among the major factors that determine the level of kinase activity of particular isoenzyme towards the pyruvate dehydrogenase complex.
40
Woods, Floyd M., and Russell Pressey. "IMMUNOLOGICAL COMPARISON OF PECTINESTERASE ISOENZYMES FROM TOMATO." HortScience 25, no. 9 (September 1990): 1085e—1085. http://dx.doi.org/10.21273/hortsci.25.9.1085e.
Full textAbstract:
Pectinesterase is present in green tomato fruit and increases several-fold during ripening. Several isoenzymes of pectinesterase can be separated by chromatography of tomato extracts on DEAE-Sephadex A-50. The predominant isoenzyme in most tomato cultivars including Better Boy has been designated PE IV. This isoenzyme accounts for most of the increase in total pectinesterase during ripening of these cultivars. The fruit of some cherry tomato cultivars such as Pixie and Short Red contain some PE IV, but the major isoenzyme is PE III which occurs only in these cultivars. PE III and PE IV were isolated from ripe fruit of Short Red and Better Boy, respectively, to further characterize differences between the isoenzymes. PE III binds more strongly to cation exchangers, indicating that it is more basic than PE IV, The molecular weights were estimated by gel filtration to be 26,900 and 25, 100 for PE III and PE IV, respectively. Polyclonal antibodies were raised against the two enzymes. Cross reactivity of the enzymes with the antibodies indicates that PE III and PE IV are immunologically identical.
41
Faulder, C. G., P. A. Hirrell, R. Hume, and R. C. Strange. "Studies of the development of basic, neutral and acidic isoenzymes of glutathione S-transferase in human liver, adrenal, kidney and spleen." Biochemical Journal 241, no. 1 (January 1, 1987): 221–28. http://dx.doi.org/10.1042/bj2410221.
Full textAbstract:
The ontogeny of basic, near-neutral and acidic glutathione S-transferase isoenzymes was studied by using chromatofocusing and ion-exchange chromatography. These isoenzyme sets demonstrated tissue-specific patterns of expression. For example, whereas basic isoenzymes were identified in all liver and adrenal cytosols obtained after 10 weeks gestation, these forms were not detected in kidney until 10 weeks post-natal age and in spleen until about 40 weeks post-natal age. Our data indicate that the basic monomers B1 and B2 are present in liver cytosol at 21 weeks gestation. Expression of the near-neutral isoenzymes was usually weak; for example, they were not generally expressed in liver until 30 weeks gestation, and no developmental patterns in their expression could be identified in adrenal, kidney and spleen. The acidic isoenzymes were usually strongly expressed in adrenal, kidney and spleen, although there was a decline in the level of expression in kidney after birth.
42
Singh, S. V., A. Kurosky, and Y. C. Awasthi. "Human liver glutathione S-transferase ψ. Chemical characterization and secondary-structure comparison with other mammalian glutathione S-transferases." Biochemical Journal 243, no. 1 (April 1, 1987): 61–67. http://dx.doi.org/10.1042/bj2430061.
Full textAbstract:
The isolation and chemical characterization of the anionic human liver glutathione S-transferase (GST) psi (pI 5.5) are described and compared with other GST isoenzymes reported for rat and human. Amino acid compositional analysis, substrate specificity and isoelectric focusing indicated that GST psi is a unique isoenzyme form of GST. Strikingly, however, amino acid sequence analysis of the N-terminal region indicated that GST psi was identical with GST mu in the first 23 amino acid residues reported. It is likely that these two enzyme forms are at least partially structurally related. In order to investigate further the genetic relationship of GST psi to other reported GST isoenzymes, secondary-structure analysis was performed. Despite substantial differences in the N-terminal-region amino acid sequences of some of the GST isoenzymes, the secondary structure of all the isoenzymes is highly conserved at their N-termini. The general uniformity of the secondary structure of this enzyme class at their N-termini strongly indicated that the observed diversity of these isoenzymes probably occurred as a result of a mechanism of gene duplication followed by divergence rather than a mechanism of convergent evolution.
43
Pearce, R. D., J. W. Callahan, P. B. Little, D. T. Armstrong, D. Kiehm, and J. T. R. Clarke. "Properties and prenatal ontogeny of β-d-mannosidase in selected goat tissues." Biochemical Journal 243, no. 2 (April 15, 1987): 603–9. http://dx.doi.org/10.1042/bj2430603.
Full textAbstract:
beta-D-Mannosidase activity in selected normal adult, neonatal and foetal goat tissues and in tissues from animals affected with caprine beta-mannosidosis was examined with the use of 4-methylumbelliferyl beta-D-mannopyranoside as substrate. The enzyme in normal adult thyroid, kidney and brain exhibited a sharp unimodal pH optimum at pH 5.0, whereas the enzyme in both normal adult and mutant liver exhibited broad pH ranges of activity (pH 4.5-8.0). No residual enzyme was detectable in mutant kidney or brain; in contrast, residual activity in mutant liver was 52% of that in a neonatal control. Concanavalin A-Sepharose 4B (Con A-Sepharose) fractionation of normal adult liver beta-D-mannosidase resolved the enzyme into an unbound (non-lysosomal) from (52%) with a broad pH range of activity (pH 4.5-8.0) and a bound (lysosomal) form (48%) with a sharp pH optimum of 5.5. The enzyme in mutant liver consisted entirely of the unbound (non-lysosomal) form. Beta-D-Mannosidase activity in normal adult thyroid, kidney and brain was resolved by chromatofocusing into two major isoenzymes, with pI 5.5 and 5.9, and traces of a minor isoenzyme, with pI 5.0. In normal adult liver the enzyme was also resolved into three isoenzymes with similar pI values; however, that with pI 5.0 predominated. The predominant form of the enzyme in 60-day-foetal liver was bound by Con A, exhibited a unimodal pH optimum (5.0) and was resolved into two isoenzymes, with pI 5.4 and 5.8; only traces of an isoenzyme with pI 5.0 were detectable. Total hepatic beta-D-mannosidase activity increased progressively towards adult values during the last 90 days of gestation as a result of increasing non-lysosomal isoenzyme activity (pI 5.0). Lysosomal beta-D-mannosidase was shown to occur in all normal goat tissues studied as multiple isoenzymes, which are genetically and developmentally distinct from the non-lysosomal isoenzyme occurring predominantly, if not exclusively, in liver.
44
Ungerer, J. P., H. M. Oosthuizen, S. H. Bissbort, and W. J. Vermaak. "Serum Adenosine Deaminase: Isoenzymes and Diagnostic Application." Clinical Chemistry 38, no. 7 (July 1, 1992): 1322–26. http://dx.doi.org/10.1093/clinchem/38.7.1322.
Full textAbstract:
Abstract Human adenosine deaminase (ADA; EC 3.5.4.4) consists of three isoenzymes: ADA1, ADA1+CP, and ADA2. We developed an electrophoretic technique to distinguish between these three isoenzymes. The isoenzyme pattern was studied in tissue and cell homogenates, as well as in serum from normal subjects and from patients with increased serum ADA who had either hepatitis, infectious mononucleosis, tuberculosis, pneumonia, rheumatoid arthritis, or acute lymphoblastic leukemia (ALL). The highest ADA activity was found in lymphocytes and monocytes. ADA2 could be detected only in monocytes (18% of total ADA activity). It was also the predominant isoenzyme in the sera of controls and all disease groups, except for ALL--the only condition evaluated that is not of an inflammatory nature. We conclude that serum ADA reflects monocyte/macrophage activity or turnover in most diseases studied. The exception is ALL, where serum ADA most probably originates from lymphocyte precursors.
45
Rotenberg, Z., I. Weinberger, E. Davidson, J. Fuchs, O. Sperling, and J. Agmon. "Patterns of lactate dehydrogenase isoenzymes in serum of patients with acute pulmonary edema." Clinical Chemistry 34, no. 9 (September 1, 1988): 1882–84. http://dx.doi.org/10.1093/clinchem/34.9.1880.
Full textAbstract:
Abstract Total lactate dehydrogenase (LD; EC 1.1.1.27) activity in serum and proportions of LD isoenzymes were quantified on admission and discharge in 170 selected (from 240) patients with acute pulmonary edema (APE). The patients were divided into group A, 75 patients with normal LD values (less than 225 U/L); and groups B-E, with increased LD activity in serum: group B, 40 patients with increase in the proportion of LD-3 (greater than 38%); group C, 12 patients with increased LD-5; group D, 36 patients with an isomorphic pattern of LD isoenzymes; and group E, seven patients with LD-1/LD-2 greater than 0.75. Nine patients in group C (75%) had also signs of right-sided congestive heart failure, 30 in group D (83%) had hypotension on admission, and six in group E (86%) had signs of recent myocardial infarction. Evidently, half of patients with APE may show increased total LD activity in serum at the time of admission. LD isoenzyme proportions should be determined in such patients, because there is no one typical pattern of LD isoenzymes and some LD isoenzyme patterns may be associated with specific clinical situations.
46
WELLER, DAVID L. "ACIDIC PEROXIDASES OF APPLE ROOTSTOCKS." Canadian Journal of Plant Science 67, no. 1 (January 1, 1987): 293–97. http://dx.doi.org/10.4141/cjps87-042.
Full textAbstract:
The peroxidase activity in extracts of shoot bark from Michigan State Apple Clone (MAC) 24 and in extracts of roots of MAC 24, East Mailing Long Ashton (EMLA) 27, and Oregon Apple Rootstock (OAR) 1 were characterized as being primarily acidic by broad range sucrose gradient isoelectric focusing. Gel isoelectric focusing (GIEF) using a narrower conventional or immobilized pH gradient showed that this activity could be separated into about a dozen isoenzymes. The GIEF isoenzyme patterns of MAC 24 shoot bark extract peroxidase and root extract peroxidases of MAC 24, EMLA 27, and OAR 1 differed. Similar values were obtained for the molecular weight of the peroxidase activity of these extracts. The results indicate that the acidic isoenzymes of apple peroxidase are of similar size.Key words: Apple, rootstocks (apple), peroxidase, molecular weight, isoenzymes
47
Bais, Renze, and Margaret Philcox. "IFCC methods for the measurement of catalytic concentration of enzymes. Part 8. IFCC method for lactate dehydrogenase (L-lactate: NAD+oxidoreductase, EC 1.1.1.27)." Journal of Automatic Chemistry 16, no. 5 (1994): 167–82. http://dx.doi.org/10.1155/s1463924694000210.
Full textAbstract:
Human lactate dehydrogenase is a tetramer made up of two types of subunits, either H (heart) or M (muscle). Combination of these subunits gives rise to the five isoenzymes of lactate dehydrogenase which are found in mammalian tissues. The relative proportions of the individual isoenzymes found in serum of patients is related to the severity of the lesion in the organ or tissue from which they originate and the half-life of the individual tissue-specific enzymes. Thus, one cannot predict the relative proportions of the different isoenzymes in any one patient sample.Lactate dehydrogenase catalyses the reversible oxidation of lactate to pyruvate and either reaction can be measured readily. However, in this method, the lactate to pyruvate reaction has been selected because of the following reasons; the time-course of the reaction is more linear, the reaction results in an increase in absorbance and optimization of substrates is possible (see appendix A).The principles applied in the selection of the conditions of measurement are those stated in previous publications by the IFCC’s Committee on Enzymes [1]. Human serum and tissue extracts have been used as the sources of enzymes. The final concentration of substrates and the pH have been selected on the basis of experiments and empirical optimization techniques and have been confirmed by calculation from rate equations. The catalytic and physical properties of the isoenzymes differ, but because of the importance of the heart specific isoenzyme (LD1) in the assessment of coronary heart disease and as a tumour marker, this method has been optimized for this isoenzyme. However, the method is also suitable, although less optimally, for the determination of the other isoenzymes of lactate dehydrogenase which may be present in serum.
48
HIRAI, Kenzo, Hiroshi TAKAYAMA, Kenjiro TOMO, and Minoru OKUMA. "Protein-tyrosine-kinase-dependent expression of cyclo-oxygenase-1 and -2 mRNAs in human endothelial cells." Biochemical Journal 322, no. 2 (March 1, 1997): 373–77. http://dx.doi.org/10.1042/bj3220373.
Full textAbstract:
Endothelial cells possess constitutive or inducible cyclo-oxygenase (COX) isoenzymes for prostacyclin production, but the mechanisms for their expression are largely unknown. We found that vanadate, an inhibitor of protein-tyrosine phosphatases, induced the expression of two COX isoenzyme mRNAs in human umbilical vein endothelial cells (HUVEC) in a time- and dose-dependent manner. Vanadate also stimulated an increase in COX-2 protein levels, but did not affect significantly the levels of constitutively expressed COX-1 protein. Synergistic enhancement of expression of the two COX isoenzyme mRNAs was observed on stimulation of HUVEC with vanadate plus interleukin-1α. Tyrphostin-47, which as an inhibitor of protein-tyrosine kinases abolished vanadate-induced protein-tyrosine phosphorylation, inhibited expression of the two COX isoenzyme mRNAs in HUVEC stimulated with vanadate or interleukin-1α. These data provide conclusive evidence that activation of protein-tyrosine kinases is causally linked to expression of the mRNAs for the two COX isoenzymes in HUVEC.
49
Hara, A., M. Hayashibara, T. Nakayama, K. Hasebe, S. Usui, and H. Sawada. "Guinea-pig liver testosterone 17 β-dehydrogenase (NADP+) and aldehyde reductase exhibit benzene dihydrodiol dehydrogenase activity." Biochemical Journal 225, no. 1 (January 1, 1985): 177–81. http://dx.doi.org/10.1042/bj2250177.
Full textAbstract:
We have kinetically and immunologically demonstrated that testosterone 17 beta-dehydrogenase (NADP+) isoenzymes (EC 1.1.1.64) and aldehyde reductase (EC 1.1.1.2) from guinea-pig liver catalyse the oxidation of benzene dihydrodiol (trans-1,2-dihydroxycyclohexa-3,5-diene) to catechol. One isoenzyme of testosterone 17 beta-dehydrogenase, which has specificity for 5 beta-androstanes, oxidized benzene dihydrodiol at a 3-fold higher rate than 5 beta-dihydrotestosterone, and showed a more than 4-fold higher affinity for benzene dihydrodiol and Vmax. value than did another isoenzyme, which exhibits specificity for 5 alpha-androstanes, and aldehyde reductase. Immunoprecipitation of guinea-pig liver cytosol with antisera against the testosterone 17 beta-dehydrogenase isoenzymes and aldehyde reductase indicated that most of the benzene dihydrodiol dehydrogenase activity in the tissue is due to testosterone 17 beta-dehydrogenase.
50
Board, P. G., and K. Pierce. "Expression of human glutathione S-transferase 2 in Escherichia coli. Immunological comparison with the basic glutathione S-transferases isoenzymes from human liver." Biochemical Journal 248, no. 3 (December 15, 1987): 937–41. http://dx.doi.org/10.1042/bj2480937.
Full textAbstract:
A plasmid, termed pTacGST2, which contains the complete coding sequence of a GST2 (glutathione S-transferase 2) subunit and permits the expression of the protein in Escherichia coli was constructed. The expressed protein had the same subunit Mr as the enzyme from normal human liver and retained its catalytic function with both GST and glutathione peroxidase activity. Antiserum raised against the bacterially synthesized protein cross-reacted with all the basic GST isoenzymes in human liver. The electrophoretic mobility in agarose of the bacterially expressed isoenzyme suggested that its pI is identical with that of the cationic isoenzyme from human liver previously termed GST2 type 1. The available evidence suggests that the three common cationic isoenzymes found in human liver are the products of two very similar gene loci.