Author:

Keywords:

Adenosine Triphosphate, Animals, Macromolecular Substances, Molecular Weight, Muscles, Phosphoprotein Phosphatase, Phosphorylase Kinase, Phosphorylase Phosphatase, Phosphorylase b, Phosphorylases, Proteins, Rabbits, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S., Science & Technology, Life Sciences & Biomedicine, Biochemistry & Molecular Biology, Biophysics, Phosphoprotein Phosphatases, 0304 Medicinal and Biomolecular Chemistry, 0601 Biochemistry and Cell Biology, 1101 Medical Biochemistry and Metabolomics, 3101 Biochemistry and cell biology, 3404 Medicinal and biomolecular chemistry

Abstract:

The dephosphorylation of phosphorylase beta kinase by the activated ATP, Mg-dependent protein phosphatase, which is highly specific for the beta-subunit, is stimulated by the deinhibitor protein which neutralizes the effect of inhibitor-1 and the modulator protein on the phosphatase. The specific dephosphorylation of the alpha-subunit of phosphorylase beta kinase by a "latent" protein phosphatase isolated from vascular smooth muscle is stimulated by histone H1 but not affected by the deinhibitor protein. These observations show that there is no strict correlation between the insensitivity of a protein phosphatase to inhibitor-1 or modulator protein and the dephosphorylation of the alpha-subunit of phosphorylase beta kinase.