Phosphorylation of skeletal muscle contractile proteins in vivo

James T. Stull, Charles W. High

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


The phosphorylation of troponin·tropomyosin and the 18,000 dalton light chain of myosin was investigated in white gracilis muscles of rabbits in vivo. Troponin·tropomyosin contained 1 mol phosphate per mol protein in resting muscle. The phosphate content was not altered by the intra-arterial injection of 1 nmol isoproterenol which increased cyclic AMP and phosphorylase a formation. Also tetanic electrical stimulation produced no change in the phosphate content of troponin·tropomyosin. The light chain of myosin contained 0.50 mol phosphate per mol protein in control muscles which increased to 0.90 with tetanic electrical stimulation. These results demonstrate that phosphorylation of myosin, but not troponin can be stimulated in skeletal muscle in vivo in response to contractile activity.

Original languageEnglish (US)
Pages (from-to)1078-1083
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number3
StatePublished - Aug 8 1977

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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