Transient state phosphate production in the hydrolysis of nucleoside triphosphates by myosin.
Transient state phosphate production in the hydrolysis of nucleoside triphosphates by myosin.
复制标题
肌球蛋白水解三磷酸核苷时产生瞬时磷酸盐。
作者：
R W Lymn;E. Taylor
用化学急冷流动装置研究了肌球蛋白对核苷三磷酸盐水解过程中稳态前的磷释放过程。在20“，pH 8.0，0.5M KCl条件下，磷酸盐的释放速率大大超过了作为底物的镁、镁和钙的稳态速率。在0.05MKCI中，以0“为底物的镁-三磷酸腺苷和20”的重肌球蛋白对镁-三磷酸腺苷的水解也有类似的结果。肌球蛋白和肌动球蛋白对核苷三磷酸盐的水解是大量研究的主题，但其机制的几个重要特征，特别是早期爆发和肌动蛋白激活的性质，人们知之甚少。最近，一些尝试
The course of presteady-state phosphate liberation in the hydrolysis of nucleoside triphosphates by myosin was studied using a chemical-quench flow apparatus. Phosphate was liberated at rates greatly exceeding the steady-state rates for MgATP, MgITP, and CaATP as substrates at 20", pH 8.0, 0.5 M KCl. Similar results were found for MgATP as substrate at 0", and for hydrolysis of MgATP at 20" by heavy meromyosin in 0.05 M KCI. The time course of the transient state hydrolysis could be fitted by a single rate T he hydrolysis of nucleoside triphosphates by myosin and actomyosin has been the subject of a large number of studies, but several important features of the mechanism, notably the nature of the early burst and of activation by actin, are poorly understood. Recently, attempts have