Equation derived from a simple kinetic model for a single-substrate non-cooperative enzyme-catalyzed reaction that successfully accounts for the hyperbolic adsorption isotherm) relationship between substrate concentration and reaction rate. V = Vmax x S/(S + Km), where V is the initial velocity of the reaction, Km is the Michaelis constant, Vmax is the maximum rate approached by very high substrate concentrations and S is the initial substrate concentration. Similar equations can be derived for conditions in which the product is present and for multisubstrate enzymes.