CREATINE PHOSPHOKINASE ACTIVITY OF MAMMALIAN ERYTHROCYTES

Abstract

Creatine phosphokinase activity was demonstrated in hemolyzates of rabbit and rat erythrocytes, but it was not present in significant amounts in human erythrocytes. Activity of the enzyme was followed by photometric estimation of the creatine liberated in the transfer of phosphate from creatine phosphate to adenosine diphosphate. The enzyme was inhibited by mercurials, heavy-metal ions, and iodoacetate, and evidently possesses free thiol groups. It required for its activation a divalent cation, such as Mg ++ or Ca ++ , but neither Na + nor K + had any effect.