Chimeric calcium/calmodulin dependent protein kinase (CCaMK) is characterized by the presence of a visinin-like Ca 2+ -binding domain unlike other known calmodulin-dependent kinases. Ca 2+ -Binding to the visinin-like domain leads to autophosphorylation and changes in the affinity for calmodulin [Sathyanarayanan ., Cremo . & Poovaiah . (2000)J. Biol. Chem. 275, 30417–30422]. Here, we report that the Ca 2+ -stimulated autophosphory-lation of CCaMK results in time-dependent loss of enzyme activity. .
