Radiochemical assays for creatine kinase and arginine kinase using rapid ion exchange separations

Simple and specific radiochemical assays for the determination of creatine and arginine kinase activities in crude tissue extracts are described. Creatine kinase is assayed by incubation with radioactive creatine and subsequent determination of the radioactivity in creatine phosphate. Creatine and creatine phosphate are separated on DEAE-cellulose ion exchange papers. Arginine kinase is assayed simllarly by using radioactive arginine and separating it from arginine phosphate on short ion exchange columns. An assay for creatine kinase in the direction of creatine formation is also described.