Dissection of enzymatic kinetics and elucidation of detailed parameters based on the Michaelis-Menten model. Kinetic and thermodynamic connections

Abstract

A computational procedure based on the numerical integration of the Michaelis-Menten model of enzyme action, free of any restrictions of steady-state conditions and substrate/enzyme ratios is proposed. The original Michaelis-Menten data for invertase (Michaelis and Menten, 1913, Biochem Z. 49:333-369) were reanalyzed. The surface and contour plots that were generated for substrate, free enzyme, complex, and product confirmed the model's usefulness. All energy potentials G and the “conformational drift parameter” δ involved in the enzymatic reactions were determined. Our findings indicate that at so = 0.0052 M the enzyme-substrate (ES) complex present an energy of dissociation of GE + S➔ES = 15.0 kJ/mol and as so increases to 0.333 M, the GE + S➔ES value decreases to 5.0 kJ/mol, thereby decreasing its presence in solution. Overall, the ability to determine G and δ for each transition suggests a relationship between kinetics and thermodynamics. The analysis proposed here can be directly applied to chemical and biological situations, as well as industrial processes.