Comparison of phosphorylation sites in protamines between protein kinase C and cAMP-dependent protein kinase.

K Nishiyama, K Sakai, Y Tanaka, T Kobayashi, S Nakamura, Y Sakanoue, E Hashimoto, H Yamamura

Index: Biochem. Int. 17(1) , 51-8, (1988)

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Abstract

Phosphorylation sites of protamines by protein kinase C and cAMP-dependent protein kinase (protein kinase A) were studied. Using clupeine Y1 as a substrate, protein kinase C phosphorylates both Ser and Thr residues, whereas protein kinase A phosphorylates only Ser residue(s). Protein kinase C phosphorylates all Ser and Thr residues of clupeine Y2 and Z, however protein kinase A phosphorylates mainly Ser9 and slightly Thr5 in clupeine Y2 and Ser6 and Ser10 in clupeine Z. These results suggest that protein kinase C recognizes more sites than those of protein kinase A and may participate in protamine phosphorylation in vivo.