The kinetics of coupled enzyme reactions. Applications to the assay of glucokinase, with glucose 6-phosphate dehydrogenase as coupling enzyme.

1. A theory is developed to account for the kinetics of coupled-enzyme reactions without assuming that the second reaction follows first-order kinetics. 2. A simple procedure is described for applying the theory to the practical design of enzyme assays. 3. The validity of the theory is confirmed for the assay of glucokinase with glucose 6-phosphate dehydrogenase as coupling enzyme. 4. The possibility of extending the theory to three or more coupled reactions is discussed.