在ATP存在的情况下，肌球蛋白DTNB轻链对肌动蛋白-肌球蛋白相互作用的影响。

Effect of myosin DTNB light chain on the actin-myosin interaction in the presence of ATP.

作者信息

Hozumi T, Hotta K

出版信息

J Biochem. 1978 Mar;83(3):671-6. doi: 10.1093/oxfordjournals.jbchem.a131959.

DOI:10.1093/oxfordjournals.jbchem.a131959

Abstract

The influence of the DTNB light chain of myosin on its enzymatic activities was examined by studying the superprecipitation of actomyosin and the actin-activated ATPase of heavy meromyosin (HMM) [EC 3.6.1.3]. Although the Ca2+-, Mg2+-, and EDTA-ATPase activities of control and DTNB myosin were practically the same, the superprecipitation of actomyosin prepared from actin and DTNB myosin occurred more slowly than that of control myosin. The apparent binding constant obtained from double-reciprocal plots of actin-activated ATPase of DTNB HMM was lower than that of control HMM. Recombination of DTNB myosin and HMM with DTNB light chains restored the original properties of myosin and HMM. The removal of DTNB light chain from myosin had no effect on the formation of the rigor complex between actin and myosin. These results suggest that the DTNB light chain participates in the interaction of myosin with actin in the presence of ATP.

摘要

通过研究肌动球蛋白的超沉淀以及重酶解肌球蛋白（HMM）[EC 3.6.1.3]的肌动蛋白激活ATP酶，考察了肌球蛋白的二硫代硝基苯甲酸（DTNB）轻链对其酶活性的影响。尽管对照肌球蛋白和DTNB肌球蛋白的Ca2 +、Mg2 +和EDTA - ATP酶活性实际上相同，但由肌动蛋白和DTNB肌球蛋白制备的肌动球蛋白的超沉淀比对照肌球蛋白发生得更慢。从DTNB HMM的肌动蛋白激活ATP酶的双倒数图获得的表观结合常数低于对照HMM。DTNB肌球蛋白和HMM与DTNB轻链的重组恢复了肌球蛋白和HMM的原始特性。从肌球蛋白中去除DTNB轻链对肌动蛋白和肌球蛋白之间强直复合物的形成没有影响。这些结果表明，在ATP存在的情况下，DTNB轻链参与了肌球蛋白与肌动蛋白的相互作用。