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Research Article Open access CC BY 4.0

A Two-part Approach to the Determination of Intrinsic Rate Constants of an Alpha-amylase Catalysed Reaction

Ikechukwu I. Udema

Asian Journal of Chemical Sciences · pp. 8–21 · Published 19 Aug 2020

10.9734/ajocs/2020/v8i219037

Abstract

Background: There is a need for equations with which to calculate the intrinsic rate constants that can further characterise enzyme catalysed reactions despite what seems to be conventional differences in methodology in the literature. Methods: Theoretical, experimental (Bernfeld method), and computational methods. Objectives: 1) To derive an alternative intrinsic rate constant equations consistent with their dimension, 2) derive electrostatic intermolecular potential energy equation, (xe), 3) calculate the intrinsic rate constants for forward (k1) and reverse (k2) reactions, and 4) define the dependence or otherwise of kinetic constants on diffusion and deduce the catalytic efficiency. Results and Discussion: The ultimate quantitative results were ~ 64.69 ±  0.49 exp (+3)/ min (k2) (and kd (s) = ~ 60.66 exp (+3)/ min), ~ 1594.48 ± 11.99 exp (+3) exp (+3) L/mol.min (k1) (and ka (s) = ~1482.47 exp (+3) L/mol.min), ~ 58.00 ± 10.83 exp (+3) /min, the apparent rate constant for reverse reaction (kb), and ~ 75.83 ± 10.83 exp (+3) /min, the rate constant for product formation (k3). The catalytic efficiency was: 3.025 exp (+ 9) L / mol.     Conclusion: The relevant equations were derived. Based on the derived equations the intrinsic rate constants can be calculated. Since k3 is > kb, then k3 is diffusion controlled and it appears that the enzyme has reached kinetic perfection. The evaluation of rate constants either from the perspective of diffusion dependency or independency cannot be valid without Avogadro number.

Aspergillus oryzea alpha-amylase apparent rate constants intrinsic rate constants intermolecular electrostatic potential energy diffusion control kinetic perfection.

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Cited by 8

Larger Intrinsic Rate Constants of Alpha-amylase is Possible if Intrinsic Forward Rate Constant is ≠ Diffusion limited Rate of Encounter

Ikechukwu I. Udema · Asian Journal of Chemical Sciences · 2022

Directly and indirectly determinable rate constants in Michaelian enzyme-catalyzed reactions

Ikechukwu Iloh Udema · 2022

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