Purified preparations of a protamine protein kinase from bovine kidney cytosol [Damuni, Amick & Sneed (1989) J. Biol. Chem. 264, 6412-6416] were inactivated after incubation with near-homogeneous preparations of protein phosphatase 2A1 and protein phosphatase 2A2. These protein phosphatase 2A-mediated inactivations of the protamine kinase were unaffected by highly purified preparations of inhibitor 2, but were prevented when the incubations were performed in the presence of 100 nM microcystin-LR, 100 nM okadaic acid or 0.2 mM-ATP. By contrast, highly purified preparations of protein phosphatase 2B, protein phosphatase 2C, the catalytic subunit of protein phosphatase 1, and two forms of a protein tyrosine phosphatase, designated PTPase 1B and T-cell PTPase, had little effect, if any, on protamine kinase activity. Purified preparations of the protamine kinase did not react with anti-phosphotyrosine antibodies, as determined by Western blotting and immunoprecipitation analysis. The results indicate that protein phosphatase 2A is a specific protamine-kinase-inactivating phosphatase.
Research Article|November 01 1992
Protein phosphatase 2A is a specific protamine-kinase-inactivating phosphatase
G D Amick;
S A G Reddy;
Biochem J (1992) 287 (3): 1019-1022.
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G D Amick, S A G Reddy, Z Damuni; Protein phosphatase 2A is a specific protamine-kinase-inactivating phosphatase. Biochem J 1 November 1992; 287 (3): 1019–1022. doi: https://doi.org/10.1042/bj2871019
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