The causes of the nonuniform thermostability of Mg-ATPase and of the contractility of muscle models
Shelud'ko, N.S.; Stadnikov, V.L.
Tsitologiia 31(2): 195-201
1989
ISSN/ISBN: 0041-3771 PMID: 2525292 Document Number: 340412
With longer periods of preliminary heat-treatment of actomyosin suspension the decrease in the rate of superprecipitation (SPP) is followed by that in the extent of SPP, and, finally, in the Mg-ATPase activity. A similar uncoupling of mechanical and enzymatic activities is observed when the ratio between the native and the inactivated myosin in reconstructed actomyosin varied. This uncoupling is supposed to result from the formation during heat-treatment of myosin bridges incapable of dissociating in the presence of Mg-ATP. The bridges affect largely the mechanical properties of actomyosin, and in a lesser degree, its enzymatic properties.