Assay and Purification of Calmodulin-Dependent Protein Kinase

Posttranslation covalent modification of proteins by phosphorylation represents an important mechanism in the control of many cellular functions (1 ,2 ). Protein kinases catalyze the transfer of the γ-phosphoryl group of ATP to an acceptor protein substrate. The activity of the enzyme is determined by the transfer of ³² P from [γ-³² P] ATP to protein substrate