由肌球蛋白、重酶解肌球蛋白、重酶解肌球蛋白亚片段1及其与肌动蛋白的复合物催化的18O交换。

18O-exchange catalyzed by myosin, heavy meromyosin, heavy meromyosin subfragment 1 and their complexes with actin.

作者信息

Panteleeva N S, Biró N A, Karandashov E A, Fábián F, Krasovskaya I E, Kuleva N V, Skvortsevich E G

出版信息

Acta Biochim Biophys Acad Sci Hung. 1977;12(1):37-44.

Abstract

Myosin, HMM and HMM S1 catalyze 18O-exchange between P1 and H218O of the medium at an intermediate stage of ATP hydrolysis ("intermediate 18O-exchange") in the presence of Mg2+. Natural complexes of actomyosin and acto-HMM S1 do not catalyze intermediate 18O-exchange but facilitate "direct" or "medium" 18O-exchange (KH2P18O4 in equilibrium H2O) even without ATP. Reconstituted complexes of actomyosin, acto-HMM, acto-HMM S1, PABC-HMM S1, congo-myosin and TNP-myosin do not catalyze direct 18O-exchange in the presence of Mg2+ and absence of ATP. From the data obtained a hypothetical sequence of phosphorylation and 18O-exchange reactions in myofibril action has been suggested.

摘要

在Mg2+存在的情况下，肌球蛋白、重酶解肌球蛋白（HMM）和HMM S1在ATP水解的中间阶段（“中间18O交换”）催化培养基中P1和H218O之间的18O交换。天然的肌动球蛋白和肌动蛋白-HMM S1复合物不催化中间18O交换，但即使没有ATP也能促进“直接”或“介质”18O交换（KH2P18O4与H2O处于平衡状态）。重组的肌动球蛋白、肌动蛋白-HMM、肌动蛋白-HMM S1、PABC-HMM S1、刚果肌球蛋白和TNP-肌球蛋白复合物在Mg2+存在且无ATP的情况下不催化直接18O交换。根据所获得的数据，提出了肌原纤维作用中磷酸化和18O交换反应的假设序列。