Effect of Insulin on Purified Creatine Phosphokinase

Abstract

THE effects of insulin can be readily demonstrated on a variety of metabolic processes in intact cells both in vivo and in vitro; however, the exact site of insulin action remains unexplained. Numerous investigators have proposed that the effects of insulin are mediated through its action on one enzyme or one enzyme system, but no such action has been consistently demonstrable. During an investigation involving the effects of insulin on certain aspects of creatine metabolism, I have found that insulin enhances the activity of a purified enzyme, creatine phosphokinase, in vitro. The reaction involved is the following : The physiological significance of this observation requires further enquiry; however, this in vitro effect is easily and consistently demonstrated.