Superprecipitation of gizzard actomyosin, and tension in gizzard muscle skinned fibers in the presence of nucleotides other than ATP

Paul Cassidy, W. G.L. Kerrick

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

1. Nucleotides which are known to be poor substrates for myosin kinase (ITP, GTP, UTP and CTP) are poor relative to ATP at producing Ca2+ -sensitive superprecipitation or tension in smooth-muscle-derived experimental systems. The ability of these nucleotides to support Ca2+ -sensitive superprecipitation or tension in striated muscle fibers depends on fiber type, but ranges from poor for GTP to excellent for CTP. 2. Thiophosphate analogs of ITP and GTP (ITPγS and GTPγS) are poor at irreversibly activating superprecipitation in smooth muscle actomyosin relative to ATPγS. 3. [γ-32P]ITP is poor relative to [γ-32P]ATP as a substrate of the endogenous myosin light-chain kinase in gizzard actomyosin. 4. The results provide further independent evidence in both gizzard actomyosin and skinned fibers that the smooth muscle Ca2+ -control system is based on myosin phosphorylation.

Original languageEnglish (US)
Pages (from-to)63-69
Number of pages7
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Volume705
Issue number1
DOIs
StatePublished - Jul 12 1982
Externally publishedYes

Keywords

  • (Gizzard muscle)
  • Actomyosin
  • Myosin phosphorylation
  • Nucleotide
  • Superprecipitation
  • Tension

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology
  • Structural Biology
  • Medicine(all)

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