COMPARISON OF THE ENZYMATIC-ACTIVITIES OF NATIVE AND RECOMBINANT PROTEIN PHOSPHATASE-1 TOWARD HISTONE

The activities of native and recombinant rabbit muscle protein phospha tase-l toward phosphorylated lysine-rich histone and phosphorylase a w ere compared. The activity of rabbit muscle protein phosphatase-l towa rd histone is strongly stimulated by Mn++. In the case of the recombin ant enzyme, both phosphorylase phosphatase and histone phosphatase act ivities exhibit a dependence on Mn++ Examination of the activities of both enzymes assayed under optimal conditions show that they exhibit s imilar substrate specificities toward histone and phosphorylase, contr ary to previous claims (Alessi et al., fur. J. Biochem. 213, 1055-1066 , 1993).