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Effect of phosphorylation on the actin-activated atpase activity of myosin

1981; Elsevier BV; Volume: 98; Issue: 3 Linguagem: Inglês

10.1016/0006-291x(81)91182-7

1090-2104

Anthony Persechini, U. Mrwa, David J. Hartshorne,

Cardiomyopathy and Myosin Studies

The purpose of this study was to test the hypothesis that the phosphorylation of myosin is solely responsible for the activation of the Mg2+-ATPase activity of gizzard actomyosin. Using a washed natural actomyosin and a reconstituted actomyosin it was shown that phosphorylation alone caused only a slight activation of ATPase activity. Full activity was obtained only when proteins in addition to the myosin light chain kinase were added. It is evident from these results that: 1) there is no simple relationship between the extent of myosin phosphorylation and the specific Mg2+-ATPase activity of actomyosin and 2) in order for full activation by actin of the Mg2+-ATPase activity of phosphorylated myosin additional factors are required.