Phosphorylation of soluble pig epidermal proteins by endogenous calcium-activated, phospholipid-dependent protein kinase.

Endogenous calcium-activated, phospholipid-dependent protein kinase phosphorylates pig epidermal protein. Pig epidermis was homogenized and centrifuged at 30,000 X g for 30 min. The supernatant was incubated with or without calcium and phospholipid. A 97 kD soluble protein from pig epidermis was phosphorylated in the presence of calcium and phosphatidylserine. The phosphorylation reaction occurred immediately. With the use of two-dimensional polyacrylamide gel electrophoresis, it was shown that the 97 kD fragment was a basic protein, and that several small proteins were also phosphorylated. The characterization of these proteins is yet to be undertaken.