Ca2+, calmodulin-dependent phosphorylation, and inactivation of glycogen synthase by a brain protein kinase

Takafumi Iwasa, Kohji Fukunaga, Hideyuki Yamamoto, Etsuro Tanaka, Eishichi Miyamoto

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

Glycogen synthase from skeletal muscle was phosphorylated by a Ca2+, calmodulin-dependent protein kinase from brain, with concomitant inactivation. About 0.7 mol phosphate/mol subunit was sufficient for a maximal inactivation of glycogen synthase. Further phosphorylation of the enzyme had no effect on the activity. The concentrations required to give half-maximal phosphorylation and inactivation of glycogen synthase were 1.1 and 0.5 μm for Ca2+, and 22 and 11 nm for calmodulin, respectively. The molar ratio of the subunit of the protein kinase to calmodulin was 2-3:1 for half-maximal phosphorylation and inactivation of glycogen synthase. The Km values for glycogen synthase and ATP were 3.6 and 114 μm, respectively, for phosphorylation. Phosphate was incorporated into sites Ia, Ib, and 2 on glycogen synthase, and site 2 was the most rapidly phosphorylated. These results indicate that the brain Ca2+, calmodulin-dependent protein kinase is probably involved in glycogen metabolism in the brain as a glycogen synthase kinase.

Original languageEnglish
Pages (from-to)212-217
Number of pages6
JournalArchives of Biochemistry and Biophysics
Volume235
Issue number1
DOIs
Publication statusPublished - 1984 Nov 15
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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