Rabbit skeletal muscle F-actin can be stable at low ionic strength, provided trace amounts of Ca2+ are absent.
Biochim Biophys Acta, 1979/4/25;577(2):267-72.
Avissar N, Kaminsky E, Leibovich SJ, Oplatka A
PMID: 110352
Abstract
Addition of low concentrations (0.2--2.0 mM) of EGTA to rabbit skeletal muscle G-actin in the presence of ATP caused increase in viscosity. The effect is probably due to chelation of Ca2+. EGTA-polymerized actin was sedimented in the ultracentrifuge as a pellet which could be depolymerized in the presence of Ca2+ and then repolymerized. Electron microscopy indicated that formation of filamentous actin which appears to be somewhat more flexible than F-actin obtained by polymerization with KCl. The EGTA-polymerized actin was dissociated by DNAase I faster than KCl-polymerized actin. F-Actin can thus be stable also in very low ionic strength media if Ca2+ is removed whereas for G-actin to be the only form of the protein in such media, micromolar concentrations of Ca2+ must be present.
MeSH terms
Actins; Animals; Biopolymers; Calcium; Drug Stability; Egtazic Acid; Muscles; Osmolar Concentration; Potassium Chloride; Rabbits; Viscosity
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