Use of Enzyme Activity Measurements in Studies on the Biochemistry of Exercise

Abstract

A theoretical basis for the use of certain enzymes, which catalyze nonequilibrium reactions, as quantitative indicators of maximum flux through metabolic pathways is described. Evidence is given that hexokinase activities indicate the maximum rate of glycolysis-from-glucose, Phosphorylase or phosphofructokinase activities indicate the maximum rate of glycolysis-from-glycogen, and oxoglutarate dehydrogenase activities indicate the maximum flux through the citric acid cycle. The latter enzyme is probably the only one that can provide quantitative information on the aerobic capacity of a muscle.