Actin and polymerization

Different smooth muscles all contain large quantities of actin ranging from about 30 to 50 mg/g wet weight, corresponding to approximately 0.9-1.6 mM in situ (Murphy et al., 1977 Hartshorne, 1987). Actin consequently accounts for between 30 and 50% of the total noncollagenous proteins in smooth muscle. As with skeletal muscle, smooth muscle actin can exist in vitro in two forms, namely, monomeric-"globular" G-actin and polymeric-filamentous F-actin. The mo-... 

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