通过增加肌球蛋白浓度来提高平滑肌肌球蛋白的肌动蛋白激活的Mg2 + -ATP酶活性。

Increase in the actin-activated Mg2+-ATPase activity of smooth muscle myosin by increasing myosin concentration.

作者信息

Higashihara M, Ikebe M

机构信息

Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106.

出版信息

Biochem Biophys Res Commun. 1988 Aug 15;154(3):928-33. doi: 10.1016/0006-291x(88)90228-8.

DOI:10.1016/0006-291x(88)90228-8

PMID:2970261

Abstract

The actin-activated Mg2+-ATPase activity of smooth muscle myosin was measured in 85 mM KCl, 6 mM MgCl2 in the absence of tropomyosin. The activity was dependent on myosin concentration. Vmax increased as myosin concentration was increased, while the Ka (the apparent dissociation constant for actin) remained the same. The extent of filament formation was also correlated with myosin concentration and most of the myosin monomers existed in 10S conformation. These results suggest that myosin concentration influences the actin-activated Mg2+-ATPase activity by changing the 10S-6S-filaments equilibrium.

摘要

在不存在原肌球蛋白的情况下，于85 mM氯化钾、6 mM氯化镁中测定平滑肌肌球蛋白的肌动蛋白激活的Mg2 + -ATP酶活性。该活性取决于肌球蛋白浓度。随着肌球蛋白浓度增加，Vmax升高，而Ka（肌动蛋白的表观解离常数）保持不变。丝形成的程度也与肌球蛋白浓度相关，并且大多数肌球蛋白单体以10S构象存在。这些结果表明，肌球蛋白浓度通过改变10S - 6S丝平衡来影响肌动蛋白激活的Mg2 + -ATP酶活性。