Michaelis-Menten kinetics

Michaelis-Menten kinetics describes the rate of enzyme-catalyzed reactions as a function of substrate concentration, formalizing the observation that reaction velocity increases with substrate concentration but saturates at a maximum rate (V_max) when all enzyme active sites are occupied. The model treats the reaction as a two-step process: enzyme binds substrate to form an enzyme-substrate complex, then the complex transforms into product and free enzyme. This is the simplest mathematical realization of the catalytic cycle in enzyme kinetics.

The two parameters of the model — V_max and the Michaelis constant K_m — capture complementary aspects of catalytic performance. V_max depends on the turnover number and total enzyme concentration; K_m reflects the substrate concentration at which the reaction operates at half-maximal velocity, integrating both binding affinity and catalytic rate. The ratio k_cat/K_m serves as a measure of catalytic efficiency, distinguishing enzymes that excel at low substrate concentrations from those that require saturation to function.