Purification and characterization of a multifunctional calmodulin-dependent protein kinase from canine myocardial cytosol

Takafumi Iwasa, Nobuhiro Inoue, Kohji Fukunaga, Toshiaki Isobe, Tsuneo Okuyama, Eishichi Miyamoto

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

A calmodulin-dependent protein kinase from canine myocardial cytosol was purified 1150-fold to apparent homogeneity with a 1.5% yield. The purified enzyme had a Mr of 550,000 with a sedimentation coefficient of 16.6 S, and showed a single protein band with a Mr of 55,000 (55K protein), determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme had a specific activity of 1.6 μmol/mg protein/min, and Ka values of 67 nM and 1.1 μM for calmodulin and Ca2+, respectively, using chicken gizzard myosin light chain as substrate. Calmodulin bound to the 55K protein. The purified enzyme had a broad substrate specificity. Endogenous proteins including glycogen synthase, phospholamban, and troponin I from the canine heart were phosphorylated by the enzyme. These results suggest that the purified enzyme works as a multifunctional protein kinase in the Ca2+, calmodulin-dependent cellular functions of the canine myocardium, and that the enzyme resembles enzymes detected in the brain, liver, and skeletal muscle.

Original languageEnglish
Pages (from-to)21-29
Number of pages9
JournalArchives of Biochemistry and Biophysics
Volume248
Issue number1
DOIs
Publication statusPublished - 1986 Jul
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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