Association of calpains 1 and 2 with protein kinase C activities.

Calpains 1 and 2 co-eluted with protein kinase C activities after hydrophobic (phenyl-Sepharose) and anion-exchange (Mono Q) chromatographies of a 100,000 X g supernatant which was defined as cytosol. After centrifugation of the cytosol at 200,000 X g for 16 h, the major part of calpain 1 and of its associated protein kinase C activity was recovered in the pellet, when the major part of calpain 2, also associated to a protein kinase C activity, was present in the resulting supernatant. Polyacrylamide gel electrophoresis of the fractions eluted from the Mono Q column, which contained calpains 1 or 2 and their associated protein kinase C activities, revealed two main bands with a molecular mass of 80 and 28 kDa.