Calcium-dependent regulation of glycogen synthase activity in a muscle glycogen particle

Ashok K. Srivastava, Balwant S. Khatra, Thomas R. Soderling

    Research output: Contribution to journalArticlepeer-review

    3 Scopus citations


    The calcium-dependent inactivation of glycogen synthase in an isolated glycogen-protein complex (glycogen pellet) from rabbit skeletal muscle has been investigated. Addition of 1 mm Ca2+, 10 mm Mg2+, and 1 mm ATP-γ-S to a concentrated suspension of glycogen pellet resulted in a rapid activation of glycogen phosphorylase concomitant with an inactivation of glycogen synthase. These conversion reactions were blocked by ethylene glycol bis(β-aminoethyl ether) N, N′-tetraacetic acid or by pretreatment of the complex with an antiserum to purified phosphorylase kinase. These data suggest that in the glycogen-protein complex, which may be a functional unit of glycogen metabolism in vivo, phosphorylase kinase can catalyze a Ca2+-dependent activation of glycogen phosphorylase synchronized with an inactivation of glycogen synthase. If under similar conditions phosphoprotein phosphatase activity was assayed using exogenous [32P]phosphorylase, there was an apparent inactivation of the phosphatase. Evidence is presented that this apparent inactivation of phosphatase was due to an accumulation of endogenous phosphorylase a which acted as an inhibitor to the exogenous [32P]-phosphorylase.

    Original languageEnglish (US)
    Pages (from-to)291-296
    Number of pages6
    JournalArchives of Biochemistry and Biophysics
    Issue number2
    StatePublished - Dec 1980

    ASJC Scopus subject areas

    • Biophysics
    • Biochemistry
    • Molecular Biology

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