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Journal articles on the topic 'Km and Vmax'

Author: Grafiati

Published: 5 June 2025

Last updated: 2 August 2025

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1

Selwood, T., та M. L. Sinnott. "One-proton catalysis by the α-l-arabinofuranosidase III of Monilinia fructigena". Biochemical Journal 254, № 3 (1988): 899–901. http://dx.doi.org/10.1042/bj2540899.

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1. Michaelis-Menten parameters for the hydrolysis of p-nitrophenyl alpha-L-arabinofuranoside were measured as a function of pL (pH or pD) in both 1H2O and 2H2O. 2. The variation of both Vmax. and Vmax./Km with pL is sigmoid, the pK governing Vmax. shifting from 6.34 +/- 0.05 in 1H2O to 6.84 +/- 0.07 in 2H2O, and that governing Vmax./Km from 5.89 +/- 0.03 in 1H2O to 6.38 +/- 0.05 in 2H2O. 3. In the plateau regions there is a small inverse solvent isotope effect on Vmax./Km (0.92), and one of 1.45 on Vmax. 4. The variation of Vmax. with isotopic composition is strictly linear, indicating that th

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2

Chike Anthony Nweze, Onyemeziri Christopher Alisa, Ali Bilar, Stanley Chinonso Ukanero, Chizoba Vivian Nweze, and Oluboyo Michael Babalola. "Comparative enzyme kinetics of catalase and dehydrogenase under municipal waste and CaO treatments in spent engine oil polluted soil." Magna Scientia Advanced Research and Reviews 14, no. 1 (2025): 173–80. https://doi.org/10.30574/msarr.2025.14.1.0069.

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This study investigates the comparative enzyme kinetics of catalase and dehydrogenase in spent engine oil (SEO)-polluted soil amended with municipal organic waste and calcium oxide (CaO). Using a Latin square design, contaminated soils were treated and monitored over 70 days. Enzyme kinetics were modeled via Michaelis-Menten and Lineweaver-Burk approaches, with kinetic parameters (Vmax and Km) determined at seven time points. On Day 1, dehydrogenase showed the lowest Km under municipal waste treatment (0.182 mM), indicating high substrate affinity, while CaO-treated soils exhibited the highest

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3

Ikechukwu Iloh Udema. "Higher precision in initial rates may be achievable: A test of a pseudo-statistical method." GSC Biological and Pharmaceutical Sciences 25, no. 1 (2023): 193–210. http://dx.doi.org/10.30574/gscbps.2023.25.1.0406.

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There has been a concerted effort at establishing the best method for the measurement of initial rates for various purposes, including the calculation of kinetic parameters, the maximum velocity (Vmax), and the Michaelis-Menten constant (KM). The objectives of this research are: 1) to derive equations without KM for the determination of the Vmax in particular and vice versa; 2) to determine the KM and Vmax with other equations other than the Michaelian equation; and 3) to subject the calculated and extrapolated kinetic parameters to pseudo-statistical remediation where necessary as a test of t

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4

Waldenlind, Elisabet, Svante B. Ross, Jan Sääf, Karl Ekbom, and Lennart Wetterberg. "Concentration and Uptake of 5-Hydroxytryptamine in Platelets from Cluster Headache and Migraine Patients." Cephalalgia 5, no. 1 (1985): 45–54. http://dx.doi.org/10.1046/j.1468-2982.1985.0501045.x.

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Concentrations of 5-hydroxytryptamine (5-HT) in platelets were determined in 33 cluster headache patients (17 males) and in 34 migraine patients (16 males) outside attacks. The 5-HT uptake into platelets was measured and the kinetic constants Vmax and Km determined in 26 cluster patients (14 males) and in 30 migraine patients (13 males). Significantly lower 5-HT concentrations in whole blood were found in cluster headache and migraine patients than in 50 healthy controls (19 males). The Vmax and Km values of the 5-HT uptake were significantly lower in cluster headache and migraine patients com

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5

Günnewich, Nils, Jonathan E. Page, Tobias G. Köllner, Jörg Degenhardt та Toni M. Kutchan. "Functional Expression and Characterization of Trichome-Specific (-)-Limonene Synthase and (+)-α-Pinene Synthase from Cannabis sativa". Natural Product Communications 2, № 3 (2007): 1934578X0700200. http://dx.doi.org/10.1177/1934578x0700200301.

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Two recombinant, stereospecific monoterpene synthases, a (-)-limonene synthase (CsTPS1) and a (+)-α-pinene synthase (CsTPS2), encoded by Cannabis sativa L. cv. ‘Skunk’ trichome mRNA, have been isolated and characterized. Recombinant CsTPS1 showed a Km value of 6.8 μM, a Vmax of 1.1 × 10−4 μmol/min and Vmax/Km of 0.016; the pH optimum was determined at pH 6.5, and a temperature optimum at 40°C. Recombinant CsTPS2 showed a Km value of 10.5 μM, a Vmax of 2.2 × 10−4 μmol/min and Vmax/Km of 0.021; the pH optimum was determined at pH 7.0, and a temperature optimum at 30°C. Phylogenetic analysis show

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6

Hormozi Jangi, Mohammad Reza, and Ali Reza Hormozi Jangi. "Determining Kinetics Parameters of Oxidase-Like Ce/Fe-Bimetallic Nanozymes Toward 3,3′,5,5′-Tetramethylbenzidine Oxidation." Archives of Case Reports: Open Access 1, no. 2 (2024): 01–05. http://dx.doi.org/10.33140/acroa.01.02.02.

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Herein, kinetics parameters, Km and Vmax, of oxidase-like Ce/Fe-bimetallic nanozymes toward 3,3′,5,5′-tetramethylbenzidine oxidation were determined. The Michaelis–Menten kinetic model was used for the evaluation of the kinetic of the nanozymemediated oxidation of 3,3′,5,5′-tetramethylbenzidine. To provide the quantitative and accurate values of kinetics parameters, Km and Vmax, the linear plot of Lineweaver–Burk was constructed. The results exhibited a Vmax as high as 67.56 nM min-1 for the oxidase-like Ce/Fe-bimetallic nanozymes. Besides, Km was found to be as low as 0.06 mM for the as-prepa

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7

Xu, Jing, and Yuqing Wang. "A Statistical Analysis on the Dependence of Tropical Cyclone Intensification Rate on the Storm Intensity and Size in the North Atlantic." Weather and Forecasting 30, no. 3 (2015): 692–701. http://dx.doi.org/10.1175/waf-d-14-00141.1.

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Abstract The dependence of tropical cyclone (TC) intensification rate IR on storm intensity and size was statistically analyzed for North Atlantic TCs during 1988–2012. The results show that IR is positively (negatively) correlated with storm intensity (the maximum sustained near-surface wind speed Vmax) when Vmax is below (above) 70–80 knots (kt; 1 kt = 0.51 m s−1), and negatively correlated with storm size in terms of the radius of maximum wind (RMW), the average radius of gale-force wind (AR34), and the outer-core wind skirt parameter DR34 (=AR34 − RMW). The turning point for Vmax of 70–80

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8

Rodríguez-Martín, A., and X. Remesar. "L-alanine transport in isolated cells of interscapular brown adipose tissue in rat." Bioscience Reports 11, no. 2 (1991): 65–71. http://dx.doi.org/10.1007/bf01119193.

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The pattern of L-alanine uptake in isolated cells of interscapular brown adipose tissue has been determined. The uptake can be divided into the diffusion component (Kd=0.55 min−1) and a saturable Na+-dependent transport (KM=0.87 mM and Vmax=155 nmol/min/106 cells). The saturable component can be subdivided into MeAIB-sensitive (KM=1.63 mM and Vmax=162 nmol/min/106 cells) and MeAIB-insensitive (KM=3.2 mM and Vmax=39.5 nmol/min/106 cells). This kinetic pattern could indicate the presence of transport system (s) that resemble the commonly described transport systems for alanine uptake in several

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9

Гребенникова, Ольга Валентиновна, Александрина Михайловна Сульман, and Елена Игоревна Шиманская. "KINETIC PARAMETERS OF THE OXIDATION OF D-GLUCOSE IN THE PRESENCE OF BIOCATALYSTS." Вестник Тверского государственного университета. Серия: Химия, no. 4(46) (December 27, 2021): 16–21. http://dx.doi.org/10.26456/vtchem2021.4.2.

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В работе были определены кинетические параметры константа Михаэлиса (Km) и максимальная скорость реакции (Vmax) для реакции окисления D-глюкозы в присутствии нативной и иммобилизованной глюкозооксидазы. Фермент был ковалентно иммобилизован на магнитоотделяемые пористые оксиды алюминия и кремния, полученные путем образования в их порах наночастиц магнетита в результате термического разложения нитрата железа. Наилучшие результаты для иммобилизованного фермента были получены для образца FeO-SiO-GOx (Km=118 мМ, Vmax=152 мкМ/мин). In this work, the kinetic parameters of the Michaelis constant (Km)

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10

Felipe, A., O. Viñas, and X. Remesar. "Changes in glycine and leucine transport during red cell maturation in the rat." Bioscience Reports 10, no. 2 (1990): 209–16. http://dx.doi.org/10.1007/bf01116580.

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Both glycine and leucine transport in rat red blood cells have been studied. The glycine uptake showed two different components, one sodium-dependent and another diffusion-like process. In contrast, leucine uptake was sodium independent. Both, Na+-dependent glycine and the overall leucine uptake in red blood cells showed a saturable pattern. Kinetic parameters in reticulocytes were: i) glycine: apparent Km 0.16 mM; Vmax 100.2 nmol/ml ICW/min; ii) leucine: apparent Km 2.11 mM; Vmax 3.88 μmol/ml ICW/min. The erythrocytes kinetic parameters were: i) glycine: apparent Km 0.17 mM; Vmax 9.47 nmol/ml

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11

Gonzalez, D. H., A. A. Iglesias, and C. S. Andreo. "Interaction of acetyl phosphate and carbamyl phosphate with plant phosphoenolpyruvate carboxylase." Biochemical Journal 241, no. 2 (1987): 543–48. http://dx.doi.org/10.1042/bj2410543.

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Acetyl phosphate produced an increase in the maximum velocity (Vmax. for the carboxylation of phosphoenolpyruvate catalysed by phosphoenolpyruvate carboxylase. The limiting Vmax. was 22.2 mumol X min-1 X mg-1 (185% of the value without acetyl phosphate). This compound also decreased the Km for phosphoenolpyruvate to 0.18 mM. The apparent activation constants for acetyl phosphate were 1.6 mM and 0.62 mM in the presence of 0.5 and 4 mM-phosphoenolpyruvate respectively. Carbamyl phosphate produced an increase in Vmax. and Km for phosphoenolpyruvate. The variation of Vmax./Km with carbamyl phospha

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12

Stinson, R. A. "Kinetic parameters for the cleaved substrate, and enzyme and substrate stability, vary with the phosphoacceptor in alkaline phosphatase catalysis." Clinical Chemistry 39, no. 11 (1993): 2293–97. http://dx.doi.org/10.1093/clinchem/39.11.2293.

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Abstract Nine different isoenzymes and (or) isoforms of alkaline phosphatase (ALP; EC 3.1.3.1) from human tissue were studied with respect to Km and Vmax values for p-nitrophenyl phosphate (p-NPP) in seven different potential phosphoacceptors/buffers. Generally, the phosphoacceptors/buffers with the lowest affinity for p-NPP (highest Km values) gave the highest Vmax values; for the nine enzyme forms in this study, the mean Km and Vmax values were greatest in 2-(ethylamino) (EAE). The two amino-propanol buffers gave the lowest Km and Vmax values. The phosphoacceptors/buffers N-methyl-D-glucamin

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13

Kaji, D. M. "Kinetics of volume-sensitive K transport in human erythrocytes: evidence for asymmetry." American Journal of Physiology-Cell Physiology 256, no. 6 (1989): C1214—C1223. http://dx.doi.org/10.1152/ajpcell.1989.256.6.c1214.

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The kinetic properties of volume-sensitive K fluxes in swollen human erythrocytes were investigated. Swelling-activated Cl-dependent K influx was a saturable function of external K concentration with a low affinity (apparent Km of 115-130 mM) and high capacity [maximal velocity (Vmax) = 20-30 mmol.l original cells-1.h-1 (mmol.loc-1.h-1)]. The Vmax and apparent Km for Cl-dependent K efflux were lower (Km = 47 mM; Vmax = 2.2 mmol.loc-1.h-1). The Hill coefficients for both K efflux and influx were close to unity, suggesting a single binding site for K. The increase of external K trans-stimulated

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14

Centelles, Josep Joan, Estefania Moreno, Pedro Ramon De Atauri, and Santiago Imperial. "Problem-Based Learning for Calculating Kinetic Parameters from Michaelis-Menten Equation." International Journal on Engineering, Science and Technology 6, no. 1 (2024): 55–67. http://dx.doi.org/10.46328/ijonest.161.

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In “Advanced Enzymology” at the University of Barcelona, we teach various methods for identifying uni-uni irreversible reactions. Kinetic constants such as maximum velocity (Vmax) and Michaelis constant (Km) are calculated using non-linear regression with the Michaelis-Menten equation. However, if a computer is not available, students must calculate these kinetic parameters using linear regressions with Lineweaver-Burk, Eadie-Hofstee, and Hanes-Woolf plots. Michaelis-Menten equation: v = (Vmax [S]) / (Km + [S]), Lineweaver-Burk equation: 1/v = (Km/Vmax) (1/[S]) + 1/Vmax, Eadie-Hofstee equation

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15

Ji, Yu Bin, Shi Yong Gao, Chen Feng Ji, and Xiang Zou. "Calculation of the Effect of Solanine on the Michaelis Constant and the Maximum Reaction Rate of NAT." Advanced Materials Research 282-283 (July 2011): 213–17. http://dx.doi.org/10.4028/www.scientific.net/amr.282-283.213.

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To explore how to calculate the effect of solanine on the Michaelis constant and the maximum reaction rate of NAT using the double reciprocal method. High performance liquid chromatography (HPLCP) was used, with 2-AF as substrate and its concentration as substrate concentration, and the rate at which 2-AF is acetylated into 2-AAF in intact HepG2 cells or in the cytoplasm of HepG2 cells as the reaction rate. The double reciprocal plot was made, with 1/S (reciprocal of the concentration of the substrate 2-AF) plotted against 1/V (reciprocal of the reaction rate), to yield a regression equation f

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16

Keller, F., C. Emde, and A. Schwarz. "Exponential function for calculating saturable enzyme kinetics." Clinical Chemistry 34, no. 12 (1988): 2486–89. http://dx.doi.org/10.1093/clinchem/34.12.2486.

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Abstract Enzyme kinetics are usually described by the Michaelis-Menten equation, where the time-dependent decrease of substrate (-dS/dt) is a hyperbolic function of maximal velocity (Vmax), Michaelis constant (Km), and amount of substrate (S). Because the Michaelis-Menten function in its most general meaning requires an assumption of steady-state, it is less curvilinear than true enzyme kinetics. A saturation-type exponential function is more curvilinear than the hyperbolic function and more closely approximates enzyme kinetics: -dS/dt = Vmax [1 - exp(-S/Km)]. The mathematical representation o

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17

Qian, Y., E. Tiffany-Castiglioni, and E. D. Harris. "Copper transport and kinetics in cultured C6 rat glioma cells." American Journal of Physiology-Cell Physiology 269, no. 4 (1995): C892—C898. http://dx.doi.org/10.1152/ajpcell.1995.269.4.c892.

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C6 rat glioma cells accumulate and efflux 67Cu. Both processes showed saturation kinetics with increasing 67Cu concentration. The Michaelis constant (Km) for uptake was 0.63 +/- 0.14 microM; maximum velocity (Vmax) was 3.29 +/- 0.57 pmol Cu.mg protein-1.min-1. The Km for efflux was 0.15 +/- 0.06 microM; Vmax was 1.08 +/- 0.71 pmol Cu.mg protein-1.min-1. p-Chloromercuribenzoate (p-CMB) totally blocked 67Cu efflux but had no effect on Km or Vmax of uptake. Total 67Cu in the cell after 50 min was partitioned equally between particulate and soluble fractions. p-CMB-treated cells accumulated more 6

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18

Sumarno, Kurnia Kusumastuti, and Junaidi Khotib. "An analysis of the Michaelis-Menten pharmacokinetics of phenytoin in epileptic Indonesian adults." Pharmacy Education 23, no. 4 (2023): 311–15. http://dx.doi.org/10.46542/pe.2023.234.311315.

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Background: Phenytoin metabolism has been shown to vary in different ethnic groups. Therefore, the authors studied phenytoin pharmacokinetics in Indonesian adult patients with epilepsy. Objective: The purpose of this study was to determine and analyse the pharmacokinetic parameters of Michaelis Menten Vmax (maximum velocity) and Km (the Michaelis constant) of phenytoin in adult epileptic patients. Method: Twelve adult epileptic patients were chosen on the basis that they had two reliable steady-state phenytoin serum levels at two different daily doses and they required an additional adjustment

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19

Jiang, Di Maria, Hao-Wen Sim, Lillian L. Siu, et al. "Cetuximab (Cet) clearance and survival in patients (pts) with metastatic colorectal cancer (mCRC)." Journal of Clinical Oncology 35, no. 15_suppl (2017): 3600. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.3600.

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3600 Background: Cet, a monoclonal antibody against EGFR, is a standard therapy for RAS wild-type (WT) mCRC. Limited data suggest a correlation between Cet clearance and progression-free survival (PFS). We performed a population pharmacokinetic (pop-pK) analysis of Cet in pts with KRAS WT mCRC who participated in the randomized phase III NCIC CO.20 trial. Methods: Standard Cet doses ± brivanib (Briv) were administered. Intermittent blood samples were obtained, and analyzed by ELISA for Cet. Pop-pK analysis was conducted to estimate Cet clearance. Pts were divided into quartiles according to cl

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20

Jiang, Di Maria, Hao-Wen Sim, Lillian L. Siu, et al. "Cetuximab (Cet) clearance and survival in patients (pts) with metastatic colorectal cancer (mCRC)." Journal of Clinical Oncology 35, no. 4_suppl (2017): 699. http://dx.doi.org/10.1200/jco.2017.35.4_suppl.699.

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699 Background: Cet, a monoclonal antibody against EGFR, is a standard therapy for pts with RAS wild-type (WT) mCRC. Limited previous data suggest that Cet clearance correlates with progression-free survival (PFS). We performed a population pharmacokinetic (pop-pK) analysis of Cet in pts who participated in the randomized phase III NCIC CO.20 trial in KRAS WT mCRC patients. Methods: Standard Cet doses ± brivanib were administered. Using intermittent trough blood samples, pop-pK analysis was conducted to evaluate different models. Pts were divided into quartiles according to clearance parameter

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21

Alderman, J. A., S. Kato, and C. S. Lieber. "Characteristics of butanol metabolism in alcohol dehydrogenase-deficient deermice." Biochemical Journal 257, no. 2 (1989): 615–17. http://dx.doi.org/10.1042/bj2570615.

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Deermice lacking the low-Km alcohol dehydrogenase eliminated butan-1-ol, a substrate for microsomal oxidation but not for catalase, at 117 mumol/min per kg body wt. Microsomal fractions and hepatocytes metabolized butan-1-ol also (Vmax. = 6.7 nmol/min per nmol of cytochrome P-450, Km = 0.85 mM; Vmax. = 5.3 nmol/min per 10(6) cells, Km = 0.71 mM respectively). These results are consistent with alcohol oxidation by the microsomal system in these deermice.

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22

Öztop, Hesna Nursevin, Fatma Banu Çatmaz, and Dursun Saraydin. "The Properties of Immobilized Invertase Onto a New Support Material; Poly(Methacrylamide/Maleic Acid) Copolymeric Hydrogel." Acta Chemica Iasi 26, no. 2 (2018): 307–28. http://dx.doi.org/10.2478/achi-2018-0019.

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Abstract Poly (methacrylamide / maleic acid) PM/MA and poly (methacrylamide) PM hydrogels were prepared aiming to be used as a support for invertase. Spectrophotometric, thermal analysis methods, swelling and diffusion experiments were used for the characterization of hydrogels. The swelling of PM/MA was higher than that of PM in water. The diffusion of water within the hydrogel was found to be non-Fickian. Invertase was immobilized onto PM and PM/MA (samples named PM-I and PM/MA-I respectively). The optimum pH values were found to be; 6.0, 5.0 and 5.5 for free invertase, PM-I and PM/MA-I resp

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23

Meno, H., J. M. Jarmakani, and K. D. Philipson. "Effect of ischemia on sarcolemmal Na+-Ca2+ exchange in neonatal hearts." American Journal of Physiology-Heart and Circulatory Physiology 256, no. 6 (1989): H1615—H1620. http://dx.doi.org/10.1152/ajpheart.1989.256.6.h1615.

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We studied the effect of cardiac ischemia on sarcolemmal enzymes, Na+-Ca2+ exchange, Ca2+ binding, and Ca2+ efflux in the newborn and adult rabbit. Rabbit ventricle was made ischemic by incubation in hypoxic, glucose-free Tyrode solution at 37 degrees C for 60-120 min. Ischemia inhibited Na+-K+-ATPase and K+-p-nitrophenylphosphatase (PNPPase) activity in the adult myocardium more than in the newborn. In the oxygenated (control) hearts, Na+-Ca2+-exchange activity in the newborn sarcolemma [Michaelis constant (Km) 18 microM; maximum velocity (Vmax) 33] was similar to that in the adult (Km = 16 m

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24

Gray, P. "The effects of systematic errors on the analysis of irreversible enzyme inhibition progress curves." Biochemical Journal 274, no. 1 (1991): 181–85. http://dx.doi.org/10.1042/bj2740181.

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The effects of errors in Km and Vmax. on the determination of the kinetic constants for the irreversible inhibition of acetylcholinesterase were determined. The results show that small errors in the values of Km and Vmax. give rise to large errors in the fitted parameters k2 and Kd. The problem may be minimized for multiple progress curves by selecting an appropriate number and distribution of inhibitor concentrations.

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25

Löfgren, Mia, Ulf Malmqvist, and Anders Arner. "Substrate and Product Dependence of Force and Shortening in Fast and Slow Smooth Muscle." Journal of General Physiology 117, no. 5 (2001): 407–18. http://dx.doi.org/10.1085/jgp.117.5.407.

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To explore the molecular mechanisms responsible for the variation in smooth muscle contractile kinetics, the influence of MgATP, MgADP, and inorganic phosphate (Pi) on force and shortening velocity in thiophosphorylated “fast” (taenia coli: maximal shortening velocity Vmax = 0.11 ML/s) and “slow” (aorta: Vmax = 0.015 ML/s) smooth muscle from the guinea pig were compared. Pi inhibited active force with minor effects on the Vmax. In the taenia coli, 20 mM Pi inhibited force by 25%. In the aorta, the effect was markedly less (&lt;10%), suggesting differences between fast and slow smooth muscl

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26

Amende, L. M., and M. A. Donlon. "Presence of a high-affinity Ca2+-and Mg2+-dependent ATPase in rat peritoneal mast-cell membranes." Biochemical Journal 226, no. 1 (1985): 335–38. http://dx.doi.org/10.1042/bj2260335.

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Purified perigranular and plasma membranes isolated from rat peritoneal mast cells were examined for Ca2+- and Mg2+-dependent ATPase activity. Isolated perigranular membranes contained only a low-affinity Ca2+- or Mg2+-dependent ATPase (Km greater than 0.5 mM). The plasma membranes contained both a low-affinity Ca2+- or Mg2+-dependent ATPase (Km = 0.4 mM, Vmax. = 20 nmol of Pi/min per mg), as well as a high-affinity Ca2+- and Mg2+-dependent ATPase (Km = 0.2 microM, Vmax. = 6 nmol of Pi/min per mg).

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27

Khandkar, M. A., E. Mukherjee, D. V. Parmar, and S. S. Katyare. "Alloxan-diabetes alters kinetic properties of the membrane-bound form, but not of the soluble form, of acetylcholinesterase in rat brain." Biochemical Journal 307, no. 3 (1995): 647–49. http://dx.doi.org/10.1042/bj3070647.

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We examined the effects of alloxan-diabetes on the kinetic properties of the soluble and the membrane-bound forms of acetylcholinesterase (AChE) in rat brain. The Km (0.15 mM) and Vmax. (1.5 mmol/min per mg of protein) of the soluble form of the enzyme were unchanged in the diabetic animals. The membrane-bound enzyme in the control group displayed a lower Km (0.09 mM) and a higher Vmax. (7.2 mmol/min per mg of protein) compared with the soluble form of the enzyme; the diabetic state caused a significant increase (40%) in both Km and Vmax. Kis values were about 3-4 times higher for the membrane

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28

Hansen, P., E. Gulve, J. Gao, J. Schluter, M. Mueckler, and J. Holloszy. "Kinetics of 2-deoxyglucose transport in skeletal muscle: effects of insulin and contractions." American Journal of Physiology-Cell Physiology 268, no. 1 (1995): C30—C35. http://dx.doi.org/10.1152/ajpcell.1995.268.1.c30.

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There is some controversy regarding whether insulin or contractile activity alters the affinity of skeletal muscle glucose transporters for glucose and its analogues. The effects of insulin and contractions on the kinetics of glucose transport were therefore reexamined in isolated rat skeletal muscles. Concentration-dependent rates of 2-deoxyglucose (2-DG) transport were measured in the absence or presence of insulin (2 mU/ml) in the epitrochlearis and split soleus muscles. The apparent half-maximal saturating substrate concentration (Km) for basal 2-DG transport (approximately 12 mM) was simi

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29

Xu, Jing, and Yuqing Wang. "Dependence of Tropical Cyclone Intensification Rate on Sea Surface Temperature, Storm Intensity, and Size in the Western North Pacific." Weather and Forecasting 33, no. 2 (2018): 523–37. http://dx.doi.org/10.1175/waf-d-17-0095.1.

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Abstract This study extends the statistical analysis on the dependence of tropical cyclone (TC) intensification rate (IR) on sea surface temperature (SST), storm initial intensity (maximum sustained surface wind speed Vmax), and storm size, in terms of the radius of maximum wind (RMW), the radius of 34-kt (AR34; 1 kt = 0.51 m s−1) wind, and the outer-core wind skirt parameter DR34 (= AR34 − RMW), for North Atlantic TCs to western North Pacific (WNP) TCs during 1982–2015. Results show that the relationship between the TC maximum potential intensification rate (MPIR) and SST also exists in the W

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30

Iloh, Udema Ikechukwu. "Linking the Pre-Steady-State, Steady-State, and Zero-Order Kinetic Parameters Together for Industrial Applications." Asian Journal of Biochemistry, Genetics and Molecular Biology 17, no. 1 (2025): 58–73. https://doi.org/10.9734/ajbgmb/2025/v17i1437.

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There appeared not to have been a way of linking pre-zero-order kinetics to zero-order kinetics so as to garner key kinetic parameters at very high industrial concentrations of the substrate. The objectives were the derivation of equations that can be explored in relating pre-zero-order (pre-steady-state (prss)) to zero-order kinetic parameters (ZOK), such as the Michaelis-Menten constant (KM), maximum velocity of catalysis (Vmax), and specificity constant (SC), to be evaluated. The Vmax for the higher industrial-type concentration of the enzyme (alpha-amylase) was 7812.5 micromoles/l/min, whi

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31

Naguib, Monir. "Kinetics of Acetate and Methanol Conversion into Methane in Eutrophic Sediments and its Application in Anaerobic Systems." Water Science and Technology 20, no. 11-12 (1988): 61–67. http://dx.doi.org/10.2166/wst.1988.0267.

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The methane production from sediments amended with acetate and methanol with and without peptone can be described by the Michaelis-Menten kinetics. The Lineweaver-Burk reciprocal plots reveal, in analogy to the kinetics of enzyme reactions, a clear defined pattern. Acetate underlies a competitive behaviour with different Km values of 7 and 2 mmolor in the absence and presence of peptone, however, with a common Vmax oF 0.3 µmoles CH4/g wet wt./d. Methanol shows, on the contrary, a non-competitive pattern with a common Km of 16.5 mmolar and different Vmax values of 0.2 and 0.5 µmoles in aged and

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32

Yakushev, A. V., А. I. Zhuravleva, and I. N. Kuznetsova. "Effect of Long-Term and Short-Term Droughts on the Hydrolytic Enzymes in Haplic Luvisol." Почвоведение, no. 6 (June 1, 2023): 745–57. http://dx.doi.org/10.31857/s0032180x2260130x.

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The transformation of organic matter in the soil is largely determined by hydrolytic enzymes. Under the conditions of climate change, understanding the mechanisms of microbial response is of particular importance for predicting the carbon cycle. Until now, the effect of drought duration and frequency on soil hydrolytic enzymes has been little studied. A multifactorial field manipulation experiment was carried out, simulating in the presence of plants and without them: two short-term droughts, a long-term drought, and an optimal level of soil moisture. The maximum reaction rate Vmax, Michaelis

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Crompton, I. E., and S. G. Waley. "The determination of specificity constants in enzyme-catalysed reactions." Biochemical Journal 239, no. 1 (1986): 221–24. http://dx.doi.org/10.1042/bj2390221.

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A convenient and accurate procedure for determining the kinetic parameter Vmax./Km is described. This avoids the error in the usual method of taking the observed first-order rate constant of an enzymic reaction at low substrate concentration as Vmax./Km. A series of reactions is used in which the initial concentration of substrate is below Km (e.g. from 5% to 50% of Km). Measurements are taken over the same extent of reaction (e.g. 70%) for each member of the series, and treated as if the kinetics were truly first-order. The reciprocal of the observed first-order rate constant is then plotted

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34

Faleev, N. G., S. N. Spirina, V. S. Ivoilov, T. V. Demidkina, and R. S. Phillips. "The Catalytic Mechanism of Tyrosine Phenol-Lyase from Erwinia herbicola: The Effect of Substrate Structure on pH-Dependence of Kinetic Parameters in the Reactions with Ring-Substituted Tyrosines." Zeitschrift für Naturforschung C 51, no. 5-6 (1996): 363–70. http://dx.doi.org/10.1515/znc-1996-5-613.

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Abstract Apparently homogeneous tyrosine phenol-lyase (TPL) from Erwinia herbicola has been prepared by a new method. The pH-dependencies of the main kinetic parameters for the reactions of Erwinia TPL with tyrosine, 2-fluorotyrosine, 3-fluorotyrosine, 2-chlorotyrosine, and 3.4-dihydroxyphenylalanine (DOPA ) have been studied. The pattern of pH-dependence of Vmax depends on the nature of the substituent in the aromatic ring. For the substrates bearing small substituents (H, 2-F, 3-F) Kmax values were found to be pH-independent. For 2-chlorotyrosine and DOPA Vmax decreased at lower pH, the effe

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35

DI IULIO, J. L., N. M. GUDE, R. G. KING, C. G. LI, M. J. RAND, and S. P. BRENNECKE. "Human placental nitric oxide synthase activity is not altered in diabetes." Clinical Science 97, no. 1 (1999): 123–28. http://dx.doi.org/10.1042/cs0970123.

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Endothelial nitric oxide synthase (NOS) protein and mRNA have been identified and calcium-dependent NOS activity has been measured in human placentae during normal pregnancy. Recently, mRNA and protein for the inducible isoform of NOS have been detected in placentae of women with gestational diabetes. The aim of this study was to determine whether calcium-independent (ciNOS) and/or total (tNOS) NOS activities were increased in placentae obtained after vaginal delivery or Caesarean section from women assigned to the following groups according to standard obstetric criteria: gestational diabetes

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36

Fernandes, M. F., R. P. M. Fernandes, J. L. Anjos, L. F. Sobral, and A. S. Araújo. "Efeito da saturação por bases sobre a atividade de fosfatases em um solo de tabuleiro costeiro cultivado com citros. II. Constantes cinéticas das enzimas." Revista Brasileira de Ciência do Solo 22, no. 3 (1998): 403–9. http://dx.doi.org/10.1590/s0100-06831998000300005.

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Determinaram-se as constantes cinéticas Km app e Vmax app de fosfatases de um solo de tabuleiro costeiro com diferentes valores de saturação por bases (32,0; 45,0; 64,0 e 76,6%). As constantes foram determinadas tanto em condições de reação com pH ótimo para atividade das fosfatases alcalinas e ácidas, quanto em valores de pH correspondentes aos de cada nível de saturação por bases. As fosfatases apresentaram cinética michaeliana, independentemente da saturação por bases ou da condição de pH utilizada para determinar a atividade enzimática. A elevação da saturação por bases resultou em redução

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37

Bosman, Gieljan J. C. G. M., and Marguerite M. B. Kay. "Alterations of band 3 transport protein by cellular aging and disease: erythrocyte band 3 and glucose transporter share a functional relationship." Biochemistry and Cell Biology 68, no. 12 (1990): 1419–27. http://dx.doi.org/10.1139/o90-205.

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Structural changes in human erythrocyte band 3 that affect anion transport are correlated with changes in glucose transport in situ. Breakdown of band 3, observed during normal erythrocyte aging in situ and in some diseases involving erythrocytes, is associated with an increase in Km and a decrease in Vmax of sulfate self-exchange, and with an increase in Km and Vmax of glucose efflux. Erythrocytes containing a high molecular weight form of band 3 exhibit an increase in Vmax of sulfate exchange and a decrease in Vmax of glucose efflux. Identical transport characteristics are observed in abnorm

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38

Haugnes, Pål, Per-Øyvind Torvik, Gertjan Ettema, Jan Kocbach, and Øyvind Sandbakk. "The Effect of Maximal Speed Ability, Pacing Strategy, and Technique on the Finish Sprint of a Sprint Cross-Country Skiing Competition." International Journal of Sports Physiology and Performance 14, no. 6 (2019): 788–95. http://dx.doi.org/10.1123/ijspp.2018-0507.

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Purpose: To investigate the contribution from maximal speed (Vmax) and %Vmax to the finish sprint speed obtained in a cross-country sprint in the classical and skating style, as well as the coinciding changes in kinematic patterns and the effect of pacing strategy on the %Vmax. Methods: Twelve elite male cross-country skiers performed two 80-m Vmax tests on flat terrain using the classical double-poling and skating G3 techniques, followed by 4 simulated 1.4-km sprint time trials, performed with conservative (controlled start) and positive (hard start) pacing strategies in both styles with a ra

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39

Nair, N., R. J. Davis, and H. L. Robinson. "Protein tyrosine kinase activities of the epidermal growth factor receptor and ErbB proteins: correlation of oncogenic activation with altered kinetics." Molecular and Cellular Biology 12, no. 5 (1992): 2010–16. http://dx.doi.org/10.1128/mcb.12.5.2010-2016.1992.

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We have compared the protein tyrosine kinase activities of the chicken epidermal growth factor receptor (chEGFR) and three ErbB proteins to learn whether cancer-activating mutations affect the kinetics of kinase activity. In immune complex assays performed in the presence of 15 mM Mn2+, ErbB proteins and the chEGFR exhibited highly reproducible tyrosine kinase activity. Under these conditions, the ErbB and chEGFR proteins had similar apparent Km [Km(app)] values for ATP. The ErbB proteins appeared to be activated, as they had at least 3-fold-higher relative Vmax(app) for autophosphorylation an

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40

Nair, N., R. J. Davis, and H. L. Robinson. "Protein tyrosine kinase activities of the epidermal growth factor receptor and ErbB proteins: correlation of oncogenic activation with altered kinetics." Molecular and Cellular Biology 12, no. 5 (1992): 2010–16. http://dx.doi.org/10.1128/mcb.12.5.2010.

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We have compared the protein tyrosine kinase activities of the chicken epidermal growth factor receptor (chEGFR) and three ErbB proteins to learn whether cancer-activating mutations affect the kinetics of kinase activity. In immune complex assays performed in the presence of 15 mM Mn2+, ErbB proteins and the chEGFR exhibited highly reproducible tyrosine kinase activity. Under these conditions, the ErbB and chEGFR proteins had similar apparent Km [Km(app)] values for ATP. The ErbB proteins appeared to be activated, as they had at least 3-fold-higher relative Vmax(app) for autophosphorylation an

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41

Lima, Augusto Miguel Nascimento, Júlio César Lima Neves, Ivo Ribeiro Silva, and Fernando Palha Leite. "Cinética de absorção e eficiência nutricional de K+, Ca2+ e Mg2+ em plantas jovens de quatro clones de eucalipto." Revista Brasileira de Ciência do Solo 29, no. 6 (2005): 903–9. http://dx.doi.org/10.1590/s0100-06832005000600008.

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Modelos mecanísticos baseados em princípios de transporte de solutos pode ser de grande utilidade para prever os impactos do cultivo de florestas plantadas, por exemplo, com eucalipto sobre o capital e fluxo de nutrientes no solo. Dentre as variáveis de entrada demandadas por tais modelos, tem-se os valores das constantes Vmax, Km e Cmin da cinética de absorção iônica. Assim, os objetivos do presente trabalho foram determinar os valores de Vmax, Km e Cmin para K, Ca e Mg, bem como avaliar as respectivas eficiências nutricionais de clones de eucalipto. O estudo consistiu de três ensaios em solu

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42

Gundo[notdef]ggmaz, G., S. Do[notdef]ggan, and O. Arslan. "Some Kinetic Properties of Polyphenol Oxidase Obtained from Various Salvia Species (Salvia Viridis L., Salvia Virgata Jacq. and Salvia Tomentosa Miller)." Food Science and Technology International 9, no. 4 (2003): 309–15. http://dx.doi.org/10.1177/108201303036476.

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Polyphenol oxidase (PPO) was partially purified by (NH4)2SO4 precipitation followed by dialysis from different organs of Salvia species (Salvia virgata Jacq., Salvia viridis L. and Salvia tomentosa Miller). Polyphenol oxidase activity was measured spectrophotometrically at 420 nm using catechol as a substrate. Vmax, KM and Vmax/KM values for polyphenol oxidase activity from different organs of Salvia species were determined. S. tomentosa Miller was the species with the highest PPO activity, followed by S. virgata Jacq and S. viridis L. S. tomentosa Miller was the most suitable Salvia species f

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43

Bandjar, Adriani, Matheis F. J. D. P. Tanasale, and Maher S. Luhukay. "Kinetic Parameters Determination Of Glucoamylase On Hydrolysis Reaction Of Sagoo Starch (Metroxylon sp)." Indonesian Journal of Chemical Research 2, no. 2 (2015): 176–81. http://dx.doi.org/10.30598/ijcr.2015.2-adr.

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Sagoo plant (Metroxylon sp.) numerous in eastern Indonesia, such as Maluku and Papua. Sagoo starch containing amylose and amylopectin. Sagoo starch hydrolysis can be carried out by enzymes, such as glucoamylase or often called amiloglukosidase or α-1 ,4-glukanoglukohidrolase, an extracellular enzyme capable hydrolyzes α-1, 4 on amylose and α-1, 6 in amylopectin. The enzymatic hydrolysis of starch can be reviewed in the kinetics of the Michaelis-Menten equation and Lineweaver-Burk equation. The aims of this study to determine the kinetic parameters (Vmax and Km) of glucoamylase on hydrolysis of

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Moalli, R., B. R. Pitt, and C. N. Gillis. "Effect of flow and surface area on angiotensin-converting enzyme activity in rabbit lungs." Journal of Applied Physiology 62, no. 5 (1987): 2042–50. http://dx.doi.org/10.1152/jappl.1987.62.5.2042.

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Pulmonary angtiotensin-converting enzyme (ACE) is located on the luminal surface of pulmonary microvasculature. Multiple indicator-dilution techniques have been used to measure pulmonary ACE activity in vivo and in isolated lungs. These studies suggest that ACE activity is depressed in several forms of acute lung injury. Depression of ACE activity may reflect impaired substrate delivery to enzyme sites because of flow-related reduction of perfused surface area. To assess the role of altered microvascular flow and surface area in the measurement of ACE activity, we utilized similar techniques t

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45

Malatesta, Francesco, and Paolo Ascenzi. "Graphical determination of ‘true’ values of Vmax and Km." Biochemical Education 21, no. 2 (1993): 88. http://dx.doi.org/10.1016/0307-4412(93)90048-5.

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46

Novak, D. A., M. S. Kilberg, and M. J. Beveridge. "Ontogeny and plasma-membrane domain localization of amino acid transport system L in rat liver." Biochemical Journal 301, no. 3 (1994): 671–74. http://dx.doi.org/10.1042/bj3010671.

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Na(+)-independent hepatic transport of branched-chain amino acids occurs via at least two distinct transport processes. System L1, characterized by micromolar Km values, predominates in hepatoma and fetal hepatocytes, whereas System L2, distinguished by Km values in the millimolar range and sensitivity to inhibition by N-ethylmaleimide (NEM), predominates in adult hepatocytes. To determine the plasma-membrane domain localization and ontogeny of System L activity in the rat, we prepared membrane vesicles from the livers of suckling (10 days old) and adult rats enriched for either basolateral (B

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47

Chand, Shekhar. "Organophosphorus pesticides stress deranged kinetic values of a few midgut carbohydrases of naiad of Trithemis aurora (burm.) (Odonata: Libellulidae)." International Journal of Agricultural Invention 1, no. 02 (2016): 155–60. http://dx.doi.org/10.46492/ijai/2016.1.2.6.

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The 40 Hrs. treatment of last instar naiad of Trithemis aurora (Burm.) in Chlorphyriphos and Quinalphos pesticides concentrations (LC50 = 5.12 ×10-7 ppm and 7.6 × 10-8 ppm) has shown significant variations in the enzyme kinetic parameters and arrested the enzymatic activity in the midgut tissue of last instar naiad of T. aurora causing deleterious effect on various carbohydrases at standard temp. and pH value. The midgut amylase ( μ and β amylase) showed the change in the velocity of enzymatic reaction under LC50 conc. of chlorpyriphos. The data of initial velocity and substrate concentration

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48

Niwa, Toshiro, and Yurie Imagawa. "Substrate Specificity of Human Cytochrome P450 (CYP) 2C Subfamily and Effect of Azole Antifungal Agents on CYP2C8." Journal of Pharmacy & Pharmaceutical Sciences 19, no. 4 (2016): 423. http://dx.doi.org/10.18433/j31s53.

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PURPOSE: The metabolic activities of aminopyrine N-demethylation and tolbutamide methylhydroxylation by the human hepatic cytochrome P450 (P450 or CYP) 2C subfamily were compared and the effects of azole antifungal agent on the drug-metabolizing activity of CYP2C8 were investigated. METHODS: Aminopyrine N-demethylation and tolbutamide methylhydroxylation by CYP2C8, CYP2C9, and CYP2C19 were determined by the previous reported methods. The effects of five azole antifungal agents, fluconazole, itraconazole, ketoconazole, miconazole, and voriconazole, on the aminopyrine N-demethylation activity by

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49

Dowell, R. T., and M. C. Fu. "Perinatal enhancement of cardiac myofibrillar creatine kinase activity without change in enzyme Km." American Journal of Physiology-Cell Physiology 265, no. 2 (1993): C375—C378. http://dx.doi.org/10.1152/ajpcell.1993.265.2.c375.

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Myofibrillar creatine kinase (CK) serves as one microcompartment of the phosphorylcreatine shuttle by providing ATP as substrate for adenosinetriphosphatase (ATPase). During perinatal heart development, augmentations of myofibrillar ATPase and CK occur in concert with increased contractile performance. The maximal reaction velocity (Vmax) for CK doubles during development in both intact native myofibril and enzyme extracted from myofibril. The absence of alterations in ADP and creatine phosphate substrate Michaelis constants (Km), isoenzyme composition, or total number of -SH groups suggests a

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50

Myers, C. L., and B. R. Pitt. "Selective effect of phorbol ester on serotonin removal and ACE activity in rabbit lungs." Journal of Applied Physiology 65, no. 1 (1988): 377–84. http://dx.doi.org/10.1152/jappl.1988.65.1.377.

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The effect of phorbol myristate acetate (PMA) on pulmonary removal of [14C]serotonin (5-[14C]HT) and metabolism of [3H]benzoyl-phenylalanyl-alanyl-proline (BPAP), a synthetic substrate for angiotensin-converting enzyme (ACE), was evaluated in isolated rabbit lungs perfused in situ with Krebs-albumin. Metabolic functions were assessed before, during, and after perfusion with 80 nM PMA (n = 11), or PMA plus 133 microM papaverine (n = 10) or PMA diluent (dimethyl sulfoxide, n = 11). Organ kinetic parameters (apparent Vmax, Km) were calculated by use of indicator-dilution techniques and by a mathe

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