Equation Validating Kinetic Parameters Must be Dimensionally Valid: General Equation of Rate Constant in Focus

Abstract

Objectives: The objectives of this research are 1) to examine the units of parameters in quasi-steady state approximation (QSSA) equations (inequalities) with a view to confirming or otherwise the dimensional consistency, 2) to slightly modify the general equation of rate constant or ES as molar concentration of enzyme involved in complex formation, 3) to justify or otherwise the shift from free substrate to total substrate intended to extend the validity of standard QSSA otherwise called total QSSA, Study Design: Theoretical and Experimental. Place and Duration of Study: Department of Chemistry and Biochemistry, Research Division of Ude International Concepts LTD (862217), B. B. Agbor, Delta State, Nigeria; Owa Alizomor Secondary School, Owa Alizomor, Ika North East, Delta State, Nigeria. The research, including the derivation of equations, lasted between 10th Jan 2018 and 3rd Mar 2018. Methodology: Bernfeld method of enzyme assay was used. Assays were carried out on Aspergillus oryzea salivary alpha-amylase. Results: The total mass concentration of substrate as against free substrate values were < total substrate concentration at the time, t = o; both rate constant and total substrate (concerning mass conservation) showed increasing trend with increasing concentration of substrate, S. Conclusion: The number of moles of each product, cannot be > the number of moles of enzyme-substrate complex. The molar concentration of bound enzyme can be calculated (Eq. 16). Equation (34) divided by molar mass gives a similar result as Eq. (16). The general rate equation needs the molar mass as denominator to be dimensionally consistent (Eq. (36)). The shift from the free substrate to "total substrate" seems valid going by the similarity between [ST] - MP and Eq. (19),           Eq. (23), and Eq. (32b). The kinetic constants seem to satisfy mainly the condition for validity of rQSSA.