心肌肌球蛋白的调节特性
Regulatory properties of myocardial myosin.
作者信息
Fenner C, Mason D T, Zelis R, Wikman-Coffelt J
出版信息
Proc Natl Acad Sci U S A. 1973 Nov;70(11):3205-9. doi: 10.1073/pnas.70.11.3205.
The ATPase activity of purified myocardial myosin was activated by either K(+) or Ca(++); the addition of one in the presence of the other caused inhibition. According to Hill-plot analyses the K(+)-saturation curves were sigmoidal (n = 2.92), while the Ca(++)-saturation curves were hyperbolic (n = 1.25). Ca(++)-saturation curves in the presence of K(+) were inhibitory with sigmoidicity (n = 4.11), while K(+)-saturation curves in the presence of Ca(++) followed the Michaelis-Menten inhibition kinetics (n = 1.11). Substrate saturation curves were hyperbolic for both Ca(++) and K(+) systems. There was no enzymatic activity when Na(+) was used as the activating metal; furthermore, Na(+) inhibited in the presence of either K(+) or Ca(++). Both Na(+) curves of inhibition followed the Michaelis-Menten relationship.
纯化心肌肌球蛋白的ATP酶活性可被K⁺或Ca²⁺激活；在另一种离子存在的情况下添加其中一种会导致抑制。根据希尔图分析，K⁺饱和曲线呈S形（n = 2.92），而Ca²⁺饱和曲线呈双曲线（n = 1.25）。在K⁺存在下的Ca²⁺饱和曲线具有抑制性且呈S形（n = 4.11），而在Ca²⁺存在下的K⁺饱和曲线遵循米氏抑制动力学（n = 1.11）。Ca²⁺和K⁺系统的底物饱和曲线均为双曲线。当使用Na⁺作为激活金属时没有酶活性；此外，Na⁺在K⁺或Ca²⁺存在时均起抑制作用。两条Na⁺抑制曲线均遵循米氏关系。
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