Studies on the reaction mechanism of skeletal muscle phosphofructokinase.

The kinetics and mechanism of action of rabbit skeletal muscle phosphofructokinase (ATP:D-fructose 6-phosphate 1 -phosphotransferase, EC 2.7.1.11) were investigated by several techniques. The initial velocity, product inhibition, isotope exchange patterns, and the result of a pulse labeling experiment are consistent with a mechanism in which ADP (or inosine diphosphate) dissociates from the enzyme before the addition of fructose 6-phosphate, and suggest the formation of phosphoryl enzyme as an intermediate. The enzyme preparation shows ATPase and fructose diphosphatase activities. The ATPase activity is catalyzed by the same protein that catalyzes the phosphofructokinase reaction.