Rate constants are determinable outside the original Michaelis–Menten mathematical formalism wherein the substrate concentration range is approx. 1.6 to 4.8 times enzyme concentration: A pre-steady-state scenario and beyond
Department of Chemistry and Biochemistry, Research Division, Ude International Concepts LTD (RC: 862217), B. B. Agbor, Delta State, Nigeria.
Research Article
World Journal of Advanced Research and Reviews, 2022, 16(01), 350–367
Publication history:
Received on 28 August 2022; revised on 12 October 2022; accepted on 15 October 2022
Abstract:
For some time now, there has been growing interest in pre-steady-state (PSS) kinetic parameters for whatever reasons, the measurement of which needs high-tech equipment capable of transient time-scale duration of assay. The proposition, however, is that all kinetic parameters, PSS and beyond, can be determined with appropriate PSS derivable equations and the usual Michaelis-Menten (MM) and Briggs-Haldane (BH) equations, respectively. The objectives of the research were: 1) To derive equations, for the determination of reverse rate constant when the substrate concentration, [S] « MM constant, KM, 2) determine by calculation, the reverse rate constant, forward rate constant, and consequently, show that it is possible to determine rate constant often seen to be masked within original MM cum BH mathematical formalism, and 3) validate corollaries from the derivation that justify procedural issue. Theoretical, experimental (Bernfeld method), and computational methods were explored. Pre-steady-state equations for the determination of kinetic parameters, the reverse rate constant, k-1, for the process ES ® E + S, the 2nd order rate constant, k1, and the rate, v1, for the formation of enzyme-substrate complex, ES, were derived. The derived originating equations with associated corollaries were validated and have been seen to be capable of reproducing experimental variables and kinetic parameters; rate constants that seemed masked in MM formalism were unmasked. Steady-state (SS) cum zero order kinetic parameters were » their PSS values. “Negative” catalytic efficiency (k-1/KM) was » “positive” catalytic efficiency, (kcat/KM), with lower [ET]. In conclusion, the equations for PSS kinetic parameters were derivable. Previously masked kinetic parameters in the MM/BB mathematical formalism can now be calculated using MM data; thus, all kinetic parameters can be determined regardless of the reaction pathway's state, PSS, and SS. PSS kinetic parameters were « SS/zero order values.
Keywords:
Aspergillus oryzea alpha-amylase; Pre-steady-state; Steady-state; Kinetic parameters; Catalytic efficiency
Full text article in PDF:
Copyright information:
Copyright © 2022 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0