Journal articles: 'And enzyme kinetics'

1

Moe, Owen, and Richard Cornelius. "Enzyme kinetics." Journal of Chemical Education 65, no. 2 (February 1988): 137. http://dx.doi.org/10.1021/ed065p137.

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2

WAGG, JONATHAN, and PETER H. SELLERS. "Enzyme Kinetics." Annals of the New York Academy of Sciences 779, no. 1 (April 1996): 272–78. http://dx.doi.org/10.1111/j.1749-6632.1996.tb44793.x.

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3

Herries, D. G. "Enzyme Kinetics." Biochemical Education 16, no. 3 (July 1988): 179–80. http://dx.doi.org/10.1016/0307-4412(88)90207-5.

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4

H.B.F.D. "Enzyme kinetics." Trends in Biochemical Sciences 13, no. 10 (October 1988): 411. http://dx.doi.org/10.1016/0968-0004(88)90200-9.

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5

Lloyd, Matthew D. "Steady-state enzyme kinetics." Biochemist 43, no. 3 (May 10, 2021): 40–45. http://dx.doi.org/10.1042/bio_2020_109.

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Steady-state enzyme kinetics is a cornerstone technique of biochemistry and related sciences since it allows the characterization and quantification of enzyme behaviour. Enzyme kinetics is widely used to investigate the physiological role of enzymes, determine the effects of mutations and characterize enzyme inhibitors. Well-known examples of enzyme inhibitors used to treat diseases include anti-infectives (e.g., penicillin, clavulanic acid and HIV protease inhibitors); anti-inflammatories (e.g., aspirin and ibuprofen); cholesterol-lowering statins; tyrosine kinase inhibitors used to treat cancer; and Viagra. Commonly, new disease treatments are discovered by using enzyme kinetics to identify the few active compounds residing within a large compound collection (‘high-throughput screening’). The subject of enzyme kinetics is typically introduced to first-year undergraduates with a mathematical description of behaviour. This Beginners Guide will give a brief overview of experimental enzyme kinetics and the characterization of enzyme inhibitors. Colorimetric assays using a microtitre plate will be considered, although most principles also apply to other assays.

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6

Guerrieri, Antonio, Rosanna Ciriello, Giuliana Bianco, Francesca De Gennaro, and Silvio Frascaro. "Allosteric Enzyme-Based Biosensors—Kinetic Behaviours of Immobilised L-Lysine-α-Oxidase from Trichoderma viride: pH Influence and Allosteric Properties." Biosensors 10, no. 10 (October 17, 2020): 145. http://dx.doi.org/10.3390/bios10100145.

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The present study describes the kinetics of L-lysine-α-oxidase (LO) from Trichoderma viride immobilised by co-crosslinking onto the surface of a Pt electrode. The resulting amperometric biosensor was able to analyse L-lysine, thus permitting a simple but thorough study of the kinetics of the immobilised enzyme. The kinetic study evidenced that LO behaves in an allosteric fashion and that cooperativity is strongly pH-dependent. Not less important, experimental evidence shows that cooperativity is also dependent on substrate concentration at high pH and behaves as predicted by the Monod-Wyman-Changeux model for allosteric enzymes. According to this model, the existence of two different conformational states of the enzyme was postulated, which differ in Lys species landing on LO to form the enzyme–substrate complex. Considerations about the influence of the peculiar LO kinetics on biosensor operations and extracorporeal reactor devices will be discussed as well. Not less important, the present study also shows the effectiveness of using immobilised enzymes and amperometric biosensors not only for substrate analysis, but also as a convenient tool for enzyme kinetic studies.

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7

Markin, C. J., D. A. Mokhtari, F. Sunden, M. J. Appel, E. Akiva, S. A. Longwell, C. Sabatti, D. Herschlag, and P. M. Fordyce. "Revealing enzyme functional architecture via high-throughput microfluidic enzyme kinetics." Science 373, no. 6553 (July 22, 2021): eabf8761. http://dx.doi.org/10.1126/science.abf8761.

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Systematic and extensive investigation of enzymes is needed to understand their extraordinary efficiency and meet current challenges in medicine and engineering. We present HT-MEK (High-Throughput Microfluidic Enzyme Kinetics), a microfluidic platform for high-throughput expression, purification, and characterization of more than 1500 enzyme variants per experiment. For 1036 mutants of the alkaline phosphatase PafA (phosphate-irrepressible alkaline phosphatase of Flavobacterium), we performed more than 670,000 reactions and determined more than 5000 kinetic and physical constants for multiple substrates and inhibitors. We uncovered extensive kinetic partitioning to a misfolded state and isolated catalytic effects, revealing spatially contiguous regions of residues linked to particular aspects of function. Regions included active-site proximal residues but extended to the enzyme surface, providing a map of underlying architecture not possible to derive from existing approaches. HT-MEK has applications that range from understanding molecular mechanisms to medicine, engineering, and design.

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8

Chisti, Yusuf. "Understanding enzyme kinetics." Biotechnology Advances 20, no. 5-6 (December 2002): 425–26. http://dx.doi.org/10.1016/s0734-9750(02)00028-9.

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9

Gutfreund, H. "Basic enzyme kinetics." FEBS Letters 212, no. 1 (February 9, 1987): 178. http://dx.doi.org/10.1016/0014-5793(87)81582-x.

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10

Louisot, P. "Basic enzyme kinetics." Biochimie 69, no. 5 (May 1987): 556–57. http://dx.doi.org/10.1016/0300-9084(87)90099-x.

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11

Cornish-Bowden, Athel. "Encyclopaedic enzyme kinetics." Trends in Biochemical Sciences 19, no. 3 (March 1994): 142. http://dx.doi.org/10.1016/0968-0004(94)90211-9.

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12

Schnell, S. "Enzyme Kinetics at High Enzyme Concentration." Bulletin of Mathematical Biology 62, no. 3 (May 2000): 483–99. http://dx.doi.org/10.1006/bulm.1999.0163.

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13

Romaní, A. M. "Characterization of extracellular enzyme kinetics in two Mediterranean streams." Fundamental and Applied Limnology 148, no. 1 (April 13, 2000): 99–117. http://dx.doi.org/10.1127/archiv-hydrobiol/148/2000/99.

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14

WU, Jia-Wei, Zhi-Xin WANG, and Jun-Mei ZHOU. "Inactivation kinetics of dihydrofolate reductase from Chinese hamster during urea denaturation." Biochemical Journal 324, no. 2 (June 1, 1997): 395–401. http://dx.doi.org/10.1042/bj3240395.

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The kinetic theory of substrate reaction during modification of enzyme activity has been applied to the study of inactivation kinetics of Chinese hamster dihydrofolate reductase by urea [Tsou (1988) Adv. Enzymol. Relat. Areas Mol. Biol. 61, 381–436]. On the basis of the kinetic equation of substrate reaction in the presence of urea, all microscopic kinetic constants for the free enzyme and enzyme–substrate binary and ternary complexes have been determined. The results of the present study indicate that the denaturation of dihydrofolate reductase by urea follows single-phase kinetics, and changes in enzyme activity and tertiary structure proceed simultaneously in the unfolding process. Both substrates, NADPH and 7,8-dihydrofolate, protect dihydrofolate reductase against inactivation, and enzyme–substrate complexes lose their activity less rapidly than the free enzyme.

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15

Tang, J. Y. "On the relationships between Michaelis–Menten kinetics, reverse Michaelis–Menten kinetics, Equilibrium Chemistry Approximation kinetics and quadratic kinetics." Geoscientific Model Development Discussions 8, no. 9 (September 3, 2015): 7663–91. http://dx.doi.org/10.5194/gmdd-8-7663-2015.

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Abstract. The Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use which of the two are often ambiguous. Here I show that these two kinetics are special approximations to the Equilibrium Chemistry Approximation kinetics, which is the first order approximation to the quadratic kinetics that solves the equation of enzyme-substrate complex exactly for a single enzyme single substrate biogeochemical reaction with the law of mass action and the assumption of quasi-steady-state for the enzyme-substrate complex and that the product genesis from enzyme-substrate complex is much slower than the equilibration between enzyme-substrate complexes, substrates and enzymes. In particular, I showed that the derivation of the Michaelis–Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis–Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in the Equilibrium Chemistry Approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis–Menten kinetics was found to persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln [ E ]T of v with respect the total enzyme concentration [ E ]T and persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln [ S ]T of v with respect to the total substrate concentration [ S ]T. Meanwhile, the reverse Michaelis–Menten kinetics persistently under-predicts ∂ ln v / ∂ ln k2+ and ∂ ln v / ∂ ln [ E ]T, and persistently over-predicts ∂ ln v / ∂ ln k1+ and ∂ ln v / ∂ ln [ S ]T. In contrast, the Equilibrium Chemistry Approximation kinetics always gives consistent predictions of ∂ ln v / ∂ ln k2+, ∂ ln v / ∂ ln k1+, ∂ ln v / ∂ ln [ E ]T and ∂ ln v / ∂ ln [ S ]T. Since the Equilibrium Chemistry Approximation kinetics includes the advantages from both the Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics and it is applicable for almost the whole range of substrate and enzyme abundances, soil biogeochemical modelers therefore no longer need to choose when to use the Michaelis–Menten kinetics or the reverse Michaelis–Menten kinetics. I expect removing this choice ambiguity will make it easier to formulate more robust and consistent land biogeochemical models.

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16

Martín, J., J. Pérez-Gil, C. Acebal, and R. Arche. "Theoretical approach to the steady-state kinetics of a bi-substrate acyl-transfer enzyme reaction that follows a hydrolysable-acyl-enzyme-based mechanism. Application to the study of lysophosphatidylcholine:lysophosphatidylcholine acyltransferase from rabbit lung." Biochemical Journal 266, no. 1 (February 15, 1990): 47–53. http://dx.doi.org/10.1042/bj2660047.

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A kinetic model is proposed for catalysis by an enzyme that has several special characteristics: (i) it catalyses an acyl-transfer bi-substrate reaction between two identical molecules of substrate, (ii) the substrate is an amphiphilic molecule that can be present in two physical forms, namely monomers and micelles, and (iii) the reaction progresses through an acyl-enzyme-based mechanism and the covalent intermediate can react also with water to yield a secondary hydrolytic reaction. The theoretical kinetic equations for both reactions were deduced according to steady-state assumptions and the theoretical plots were predicted. The experimental kinetics of lysophosphatidylcholine:lysophosphatidylcholine acyltransferase from rabbit lung fitted the proposed equations with great accuracy. Also, kinetics of inhibition by products behaved as expected. It was concluded that the competition between two nucleophiles for the covalent acyl-enzyme intermediate, and not a different enzyme action depending on the physical state of the substrate, is responsible for the differences in kinetic pattern for the two activities of the enzyme. This conclusion, together with the fact that the kinetic equation for the transacylation is quadratic, generates a ‘hysteretic’ pattern that can provide the basis of self-regulatory properties for enzymes to which this model could be applied.

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17

Fink, A. M. "Optimal control in liver kinetics." Journal of the Australian Mathematical Society. Series B. Applied Mathematics 27, no. 3 (January 1986): 361–69. http://dx.doi.org/10.1017/s0334270000004987.

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AbstractWe solve a minimization problem in liver kinetics posed by Bass, et al., in this journal, (1984), pages 538–562. The problem is to choose the density functions for the location of two enzymes, in order to minimize the concentration of an intermediate form of a substance at the outlet of the liver. This form may be toxic to the rest of the body, but the second enzyme renders it harmless. It seems natural that the second enzyme should be downstream from the first. However, we can show that the minimum problem is sometimes solved by an overlap of the supports of the two density functions. Even more surprising is that, for certain forms of the kinetic functions and high levels of transformation of the first enzymatic reaction, some of the first enzyme should be located downstream from all the second enzyme. This suggests that the first reaction should be relatively slow.

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18

Tang, J. Y. "On the relationships between the Michaelis–Menten kinetics, reverse Michaelis–Menten kinetics, equilibrium chemistry approximation kinetics, and quadratic kinetics." Geoscientific Model Development 8, no. 12 (December 1, 2015): 3823–35. http://dx.doi.org/10.5194/gmd-8-3823-2015.

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Abstract. The Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use either of the two are often ambiguous. Here I show that these two kinetics are special approximations to the equilibrium chemistry approximation (ECA) kinetics, which is the first-order approximation to the quadratic kinetics that solves the equation of an enzyme–substrate complex exactly for a single-enzyme and single-substrate biogeochemical reaction with the law of mass action and the assumption of a quasi-steady state for the enzyme–substrate complex and that the product genesis from enzyme–substrate complex is much slower than the equilibration between enzyme–substrate complexes, substrates, and enzymes. In particular, I show that the derivation of the Michaelis–Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis–Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in deriving the equilibrium chemistry approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis–Menten kinetics was found to persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln [E]T of v with respect the total enzyme concentration [E]T, and persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln [S]T of v with respect to the total substrate concentration [S]T. Meanwhile, the reverse Michaelis–Menten kinetics persistently underpredicts ∂ ln v / ∂ ln k2+ and ∂ ln v / ∂ ln [E]T, and persistently overpredicts ∂ ln v / ∂ ln k1+ and ∂ ln v / ∂ ln [S]T. In contrast, the equilibrium chemistry approximation kinetics always gives consistent predictions of ∂ ln v / ∂ ln k2+, ∂ ln v / ∂ ln k1+, ∂ ln v / ∂ ln [E]T, and ∂ ln v / ∂ ln [S]T, indicating that ECA-based models will be more calibratable if the modeled processes do obey the law of mass action. Since the equilibrium chemistry approximation kinetics includes advantages from both the Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics and it is applicable for almost the whole range of substrate and enzyme abundances, land biogeochemical modelers therefore no longer need to choose when to use the Michaelis–Menten kinetics or the reverse Michaelis–Menten kinetics. I expect that removing this choice ambiguity will make it easier to formulate more robust and consistent land biogeochemical models.

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19

Meilany, Diah, Efri Mardawati, Made Tri Ari Penia Kresnowati, and Tjandra Setiadi. "KINETIC STUDY OF OIL PALM EMPTY FRUIT BUNCH ENZYMATIC HYDROLYSIS." Reaktor 17, no. 4 (February 2, 2018): 197. http://dx.doi.org/10.14710/reaktor.17.4.197-202.

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As lignocellulosic biomass, Oil Palm Empty Fruit Bunch (OPEFB) can be used as the source of xylose that can be further utilized as the raw material for xylitol production. The processing of OPEFB to xylose comprises of pretreatment and hydrolysis that can be performed enzymatically. This process offers the advantages of moderate operation conditions and more environmentally friendly. This article describes the kinetic study of enzymatic hydrolysis process of OPEFB for producing xylose using self-prepared and commercial xylanase enzymes. Despite the possible mass transfer limitation, the Michaelis Menten kinetics was hypothesized. The results indicated that the reaction at pH 5 and 60°C followed the Michaelis Menten kinetics, with Vm of 0.84 g/L-h and Km of 48.5 g/L for the commercial enzyme, and Vm of 0,38 g/L-h and Km of 0,37 g/L for the self-prepared enzyme. The reaction is affected by temperature, with Ea of 8.6 kcal/gmol. The performance of self-prepared xylanase enzyme was not yet as good as the commercial enzyme, Cellic Htec 2. Keywords: enzymatic hydrolysis; kinetics parameter; OPEFB; xylanase; xylose

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20

Alberty, Robert A. "Rapid-Equilibrium Enzyme Kinetics." Journal of Chemical Education 85, no. 8 (August 2008): 1136. http://dx.doi.org/10.1021/ed085p1136.

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21

DAGANI, RON. "STRAIGHTENING OUT ENZYME KINETICS." Chemical & Engineering News Archive 81, no. 24 (June 16, 2003): 26. http://dx.doi.org/10.1021/cen-v081n024.p026.

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22

Selwyn, MJ. "Fundamentals of enzyme kinetics." Biochemical Education 24, no. 1 (January 1996): 63. http://dx.doi.org/10.1016/s0307-4412(96)80014-8.

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23

Zimmerman, James. "Enzyme kinetics and mechanism." Biochemistry and Molecular Biology Education 35, no. 5 (2007): 387. http://dx.doi.org/10.1002/bmb.88.

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24

McDonald, A. G. "Implications of enzyme kinetics." Biochemical Society Transactions 31, no. 3 (June 1, 2003): 719–22. http://dx.doi.org/10.1042/bst0310719.

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Of the many examples of oscillatory kinetic behaviour known, several are briefly reviewed, including those of glycolysis, the peroxidase–oxidase reaction and oscillations in cellular calcium concentration. It is shown that simple mathematical models employing allosteric rate laws are sufficient to explain the instability of the steady state and the appearance of sustained oscillations. The cAMP-signalling systems of cellular slime moulds and the dynamics of intracellular calcium oscillations illustrate the importance of such oscillophores to inter- and intra-cellular communication and differentiation.

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25

Byerley, Jennifer, Jin Zhou, and Aaron Teitelbaum. "UGT1A8: Atypical enzyme kinetics." Drug Metabolism and Pharmacokinetics 33, no. 1 (January 2018): S54. http://dx.doi.org/10.1016/j.dmpk.2017.11.185.

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26

Maxwell, A. "In focus: Enzyme kinetics." FEBS Letters 238, no. 1 (September 26, 1988): 217–18. http://dx.doi.org/10.1016/0014-5793(88)80262-x.

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27

HAPPEL, JOHN, and PETER H. SELLERS. "ENZYME MECHANISM AND KINETICS*." Chemical Engineering Communications 152-153, no. 1 (October 1996): 433–68. http://dx.doi.org/10.1080/00986449608936577.

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28

Crabbe, M. James C., and Derek Goode. "Nonlinear steady-state kinetics of chloramphenicol acetyltransferase." Biochemistry and Cell Biology 69, no. 9 (September 1, 1991): 630–34. http://dx.doi.org/10.1139/o91-093.

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Steady-state kinetic analysis of chloramphenicol acetyltransferase showed that medium effects (higher temperatures or pH, higher ionic strengths, or lower values for dielectric constant) altered the kinetic behaviour of the enzyme with acetyl-CoA as substrate, but did not significantly affect behaviour with chloramphenicol. This was manifest as an increase in the degree of the rate equation to a 2:2 function. This is interpreted in terms of perturbations to the enzyme at or near the acetyl-CoA binding region of the enzyme.Key words: acetyl coenzyme A, chloramphenicol, antibiotics, enzyme kinetics.

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29

Vannoy, Kathryn J., Andrey Ryabykh, Andrei I. Chapoval, and Jeffrey E. Dick. "Single enzyme electroanalysis." Analyst 146, no. 11 (2021): 3413–21. http://dx.doi.org/10.1039/d1an00230a.

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Traditional enzymology relies on the kinetics of millions of enzymes, an experimental approach that may wash out heterogeneities between individual enzymes. Electrochemical methods have emerged in the last 5 years to probe single enzyme reactivity.

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30

Duskey, Jason Thomas, Federica da Ros, Ilaria Ottonelli, Barbara Zambelli, Maria Angela Vandelli, Giovanni Tosi, and Barbara Ruozi. "Enzyme Stability in Nanoparticle Preparations Part 1: Bovine Serum Albumin Improves Enzyme Function." Molecules 25, no. 20 (October 9, 2020): 4593. http://dx.doi.org/10.3390/molecules25204593.

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Enzymes have gained attention for their role in numerous disease states, calling for research for their efficient delivery. Loading enzymes into polymeric nanoparticles to improve biodistribution, stability, and targeting in vivo has led the field with promising results, but these enzymes still suffer from a degradation effect during the formulation process that leads to lower kinetics and specific activity leading to a loss of therapeutic potential. Stabilizers, such as bovine serum albumin (BSA), can be beneficial, but the knowledge and understanding of their interaction with enzymes are not fully elucidated. To this end, the interaction of BSA with a model enzyme B-Glu, part of the hydrolase class and linked to Gaucher disease, was analyzed. To quantify the natural interaction of beta-glucosidase (B-Glu,) and BSA in solution, isothermal titration calorimetry (ITC) analysis was performed. Afterwards, polymeric nanoparticles encapsulating these complexes were fully characterized, and the encapsulation efficiency, activity of the encapsulated enzyme, and release kinetics of the enzyme were compared. ITC results showed that a natural binding of 1:1 was seen between B-Glu and BSA. Complex concentrations did not affect nanoparticle characteristics which maintained a size between 250 and 350 nm, but increased loading capacity (from 6% to 30%), enzyme activity, and extended-release kinetics (from less than one day to six days) were observed for particles containing higher B-Glu:BSA ratios. These results highlight the importance of understanding enzyme:stabilizer interactions in various nanoparticle systems to improve not only enzyme activity but also biodistribution and release kinetics for improved therapeutic effects. These results will be critical to fully characterize and compare the effect of stabilizers, such as BSA with other, more relevant therapeutic enzymes for central nervous system (CNS) disease treatments.

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31

Pyne, N. J., M. E. Cooper, and M. D. Houslay. "Identification and characterization of both the cytosolic and particulate forms of cyclic GMP-stimulated cyclic AMP phosphodiesterase from rat liver." Biochemical Journal 234, no. 2 (March 1, 1986): 325–34. http://dx.doi.org/10.1042/bj2340325.

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Two enzymes displaying cyclic GMP-stimulated cyclic AMP phosphodiesterase activity were purified from rat liver to apparent homogeneity: a ‘particulate enzyme’ found as an integral membrane protein associated with the plasma membrane, and a ‘soluble’ enzyme found in the cytosol. The physical properties of these enzymes were very similar, being dimers of Mr 134,000, composed in each instance of two subunits of Mr = 66,000-67,000. Both enzymes showed similar kinetics for cyclic AMP hydrolysis. They are both high-affinity enzymes, with kinetic constants for the particulate enzyme of Km = 34 microM and Vmax. = 4.0 units/mg of protein and for the cytosolic enzyme Km = 40 microM and Vmax. = 4.8 units/mg of protein. In both instances hydrolysis of cyclic AMP appeared to show apparent positive co-operativity, with Hill coefficients (happ.) of 1.5 and 1.6 for the particulate and cytosolic enzymes respectively. However, in the presence of 2 microM-cyclic GMP, the hydrolysis of cyclic AMP obeyed Michaelis kinetics (happ. = 1) for both enzymes. The addition of micromolar concentrations of cyclic GMP had little effect on the Vmax. for cyclic AMP hydrolysis, but lowered the Km for cyclic AMP hydrolysis to around 20 microM in both cases. However, at low cyclic AMP substrate concentrations, cyclic GMP was a more potent activator of the particulate enzyme than was the soluble enzyme. The activity of these enzymes could be selectively inhibited by cis-16-palmitoleic acid and by arachidonic acid. In each instance, however, the hydrolysis of cyclic AMP became markedly more sensitive to such inhibition when low concentrations of cyclic GMP were present. Tryptic peptide maps of iodinated preparations of these two purified enzyme species showed that there was considerable homology between these two enzyme forms.

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32

WANG, Ming-Hua, Zhi-Xin WANG, and Kang-Yuan ZHAO. "Kinetics of inactivation of bovine pancreatic ribonuclease A by bromopyruvic acid." Biochemical Journal 320, no. 1 (November 15, 1996): 187–92. http://dx.doi.org/10.1042/bj3200187.

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The kinetic theory of substrate reaction during the modification of enzyme activity [Duggleby (1986) J. Theor. Biol. 123, 67–80; Wang and Tsou (1990) J. Theor. Biol. 142, 531–549] has been applied to a study of the inactivation kinetics of ribonuclease A by bromopyruvic acid. The results show that irreversible inhibition belongs to a non-competitive complexing type inhibition. On the basis of the kinetic equation of substrate reaction in the presence of the inhibitor, all microscopic kinetic constants for the free enzyme, the enzyme–substrate complex and the enzyme–product complex have been determined. The non-competitive inhibition type indicates that neither the substrate nor the product affects the binding of bromopyruvic acid to the enzyme and that the ionization state of His-119 may be the same in both the enzyme–substrate and the enzyme–product complexes.

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33

Purich, Daniel L. "Enzyme kinetics: From diastase to multi-enzyme systems." Chemistry & Biology 2, no. 7 (July 1995): 449–50. http://dx.doi.org/10.1016/1074-5521(95)90261-9.

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34

Wang, Z. X., H. B. Wu, X. C. Wang, H. M. Zhou, and C. L. Tsou. "Kinetics of the course of inactivation of aminoacylase by 1,10-phenanthroline." Biochemical Journal 281, no. 1 (January 1, 1992): 285–90. http://dx.doi.org/10.1042/bj2810285.

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The kinetic theory of the substrate reaction during modification of enzyme activity previously described [Tsou (1988) Adv. Enzymol. Relat. Areas Mol. Biol. 61, 381-436] has been applied to a study on the kinetics of the course of inactivation of aminoacylase by 1,10-phenanthroline. Upon dilution of the enzyme that had been incubated with 1,10-phenanthroline into the reaction mixture, the activity of the inhibited enzyme gradually increased, indicating dissociation of a reversible enzyme–1,10-phenanthroline complex. The kinetics of the substrate reaction with different concentrations of the substrate chloroacetyl-L-alanine and the inactivator suggest a complexing mechanism for inactivation by, and substrate competition with, 1,10-phenanthroline at the active site. The inactivation kinetics are single phasic, showing that the initial formation of an enzyme-Zn(2+)-1,10-phenanthroline complex is a relatively rapid reaction, followed by a slow inactivation step that probably involves a conformational change of the enzyme. The presence of Zn2+ apparently stabilizes an active-site conformation required for enzyme activity.

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35

Hochendoner, Philip, Curtis Ogle, and William H. Mather. "A queueing approach to multi-site enzyme kinetics." Interface Focus 4, no. 3 (June 6, 2014): 20130077. http://dx.doi.org/10.1098/rsfs.2013.0077.

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Multi-site enzymes, defined as where multiple substrate molecules can bind simultaneously to the same enzyme molecule, play a key role in a number of biological networks, with the Escherichia coli protease ClpXP a well-studied example. These enzymes can form a low latency ‘waiting line’ of substrate to the enzyme's catalytic core, such that the enzyme molecule can continue to collect substrate even when the catalytic core is occupied. To understand multi-site enzyme kinetics, we study a discrete stochastic model that includes a single catalytic core fed by a fixed number of substrate binding sites. A natural queueing systems analogy is found to provide substantial insight into the dynamics of the model. From this, we derive exact results for the probability distribution of the enzyme configuration and for the distribution of substrate departure times in the case of identical but distinguishable classes of substrate molecules. Comments are also provided for the case when different classes of substrate molecules are not processed identically.

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36

Rodriguez, Jon-Marc G., and Marcy H. Towns. "Analysis of student reasoning about Michaelis–Menten enzyme kinetics: mixed conceptions of enzyme inhibition." Chemistry Education Research and Practice 20, no. 2 (2019): 428–42. http://dx.doi.org/10.1039/c8rp00276b.

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Student understanding regarding topics in upper-division courses, such as biochemistry, is not well represented in the literature. Herein we describe a study that investigated students’ reasoning about Michaelis–Menten enzyme kinetics and enzyme inhibition. Our qualitative study involved semistructured interviews with fourteen second-year students enrolled in an introductory biochemistry course. During the interviews students were provided an enzyme kinetics graph, which they were prompted to describe. Students were asked to look for patterns and trends in the data and interpret the graph to draw conclusions regarding the types of enzyme inhibition observed, providing the opportunity for the students to engage in the science practiceanalyzing and interpreting data. Findings indicate students were able to attend to the relevant parameters (V_maxandK_m) in the graph and subsequently associate changes inV_maxandK_mto different types of enzyme inhibitors. However, students expressed difficulty explaining why a specific type of inhibition caused the observed change in the kinetic parameters and there was confusion regarding the distinction between noncompetitive and uncompetitive inhibition. Based on our results, we suggest instruction on enzyme kinetics should emphasize qualitative descriptions of the particulate-level mechanisms related to competitive and noncompetitive inhibition, with less emphasis on discussions of uncompetitive and mixed inhibition in introductory biochemistry courses.

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37

Blackmore, R. S., T. Brittain, and C. Greenwood. "An analysis of the reaction kinetics of the hexahaem nitrite reductase of the anaerobic rumen bacterium Wolinella succinogenes." Biochemical Journal 271, no. 2 (October 15, 1990): 457–61. http://dx.doi.org/10.1042/bj2710457.

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The reduction kinetics of both the resting and redox-cycled forms of the nitrite reductase from the anaerobic rumen bacterium Wolinella succinogenes were studied by stopped-flow reaction techniques. Single-turnover reduction of the enzyme by dithionite occurs in two kinetic phases for both forms of the enzyme. When the resting form of the enzyme is subjected to a single-turnover reduction by dithionite, the slower of the two kinetic phases exhibits a hyperbolic dependence of the rate constant on the square root of the reductant concentration, the limiting value of which (approximately 4 s-1) is assigned to a slow internal electron-transfer process. In contrast, when the redox-cycled form of the enzyme is reduced by dithionite in a single-turnover experiment, both kinetic phases exhibit linear dependences of the rate on the square root of dithionite concentration, with associated rate constants of 150 M-1/2.s-1 and 6 M-1/2.s-1. Computer simulations of both the reduction processes shows that no unique set of rate constants can account for the kinetics of both forms, although the kinetics of the redox-cycled species is consistent with a much enhanced rate of internal electron transfer. Under turnover conditions the time course for reduction of the enzyme, in the presence of millimolar levels of nitrite and 100 mM-dithionite, is extremely complex. A working model for the mechanism of the turnover activity of the enzyme is proposed which very closely describes the reaction kinetics over a wide range of substrate concentrations, as shown by computer simulation. The similarity in the action of the nitrite reductase enzyme and mammalian cytochrome c oxidase is commented upon.

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38

DE ATAURI, Pedro, Luis ACERENZA, Boris N. KHOLODENKO, Núria DE LA IGLESIA, Joan J. GUINOVART, Loranne AGIUS, and Marta CASCANTE. "Occurrence of paradoxical or sustained control by an enzyme when overexpressed: necessary conditions and experimental evidence with regard to hepatic glucokinase." Biochemical Journal 355, no. 3 (April 24, 2001): 787–93. http://dx.doi.org/10.1042/bj3550787.

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It is widely assumed that the control coefficient of an enzyme on pathway flux decreases as the concentration of enzyme increases. However, it has been shown [Kholodenko and Brown (1996) Biochem. J. 314, 753–760] that enzymes with sigmoidal kinetics can maintain or even gain control with an increase in enzyme activity or concentration. This has been described as ‘paradoxical control’. Here we formulate the general requirements for allosteric enzyme kinetics to display this behaviour. We show that a necessary condition is that the Hill coefficient of the enzyme should increase with an increase in substrate concentration or decrease with an increase in product concentration. We also describe the necessary and sufficient requirements for the occurrence of paradoxical control in terms of the flux control coefficients and the derivatives of the elasticities. The derived expression shows that the higher the control coefficient of an allosteric enzyme, the more likely it is that the pathway will display this behaviour. Control of pathway flux is generally shared between a large number of enzymes and therefore the likelihood of observing sustained or increased control is low, even if the kinetic parameters are in the most favourable range to generate the phenomenon. We show that hepatic glucokinase, which has a very high flux control coefficient and displays sigmoidal behaviour within the hepatocyte in situ as a result of interaction with a regulatory protein, displays sustained or increased control over an extended range of enzyme concentrations when the regulatory protein is overexpressed.

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39

Benner, Steven A. "Enzyme kinetics and molecular evolution." Chemical Reviews 89, no. 4 (June 1989): 789–806. http://dx.doi.org/10.1021/cr00094a004.

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40

Yang, Song Yu, and Horst Schulz. "Kinetics of coupled enzyme reactions." Biochemistry 26, no. 17 (August 25, 1987): 5579–84. http://dx.doi.org/10.1021/bi00391a054.

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41

Crabbe, M. James C. "Enzyme kinetics: a modern approach." Computational Biology and Chemistry 27, no. 2 (May 2003): 161–62. http://dx.doi.org/10.1016/s1476-9271(02)00103-2.

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42

Bailey, C. J. "Enzyme kinetics of cellulose hydrolysis." Biochemical Journal 262, no. 3 (September 15, 1989): 1001. http://dx.doi.org/10.1042/bj2621001a.

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43

Xie, X. S. "Enzyme Kinetics, Past and Present." Science 342, no. 6165 (December 19, 2013): 1457–59. http://dx.doi.org/10.1126/science.1248859.

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44

Hurtley, S. M. "Enzyme Kinetics in Living Color." Science's STKE 2007, no. 368 (January 9, 2007): tw17. http://dx.doi.org/10.1126/stke.3682007tw17.

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45

Benka, Stephen G. "Zooming in on enzyme kinetics." Physics Today 59, no. 4 (April 2006): 9. http://dx.doi.org/10.1063/1.2207009.

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46

Sobolev, V. "Decomposition of enzyme kinetics equations." Journal of Physics: Conference Series 1368 (November 2019): 042008. http://dx.doi.org/10.1088/1742-6596/1368/4/042008.

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47

HIROMI, Keitaro. "Some Developments in Enzyme Kinetics." Journal of the agricultural chemical society of Japan 66, no. 9 (1992): 1319–26. http://dx.doi.org/10.1271/nogeikagaku1924.66.1319.

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48

Thilakavathi, Mani, Tanmay Basak, and Tapobrata Panda. "Modeling of enzyme production kinetics." Applied Microbiology and Biotechnology 73, no. 5 (January 2007): 991–1007. http://dx.doi.org/10.1007/s00253-006-0667-0.

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49

Cornish-Bowden, Athel. "The origins of enzyme kinetics." FEBS Letters 587, no. 17 (June 19, 2013): 2725–30. http://dx.doi.org/10.1016/j.febslet.2013.06.009.

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50

Demetrius, Lloyd. "Selective neutrality and enzyme kinetics." Journal of Molecular Evolution 45, no. 4 (October 1997): 370–77. http://dx.doi.org/10.1007/pl00006242.

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Journal articles on the topic 'And enzyme kinetics'

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