ABSTRACT
A rate expression may be written for each of the molar species that occur in a reaction. To express a rate change in a quantitative fashion, it is of great advantage to derive proper mathematical equations that express the changes in concentrations of reactant and product during the reaction. Therefore, when the rate of a chemical reaction may be described by a simple stoichiometric equation, it is possible to define a rate of reaction for the system uniquely. In the reactions considered so far, the coefficients in front of the reactants and products of the stoichiometric equations are unity. The enzyme-substrate complex, EA, is an obligatory intermediate in the reaction as written. The case of consecutive reactions is to be contrasted to the case of simultaneous reactions. Zero-order reactions, with respect to substrate, are encountered whenever the enzyme is saturated with substrate.
