大鼠肌肉中AMP脱氨酶与肌球蛋白的相互作用。I. 大鼠肌肉中AMP脱氨酶与肌球蛋白相互作用的生化研究。

Interaction of rat muscle AMP deaminase with myosin. I. Biochemical study of the interaction of AMP deaminase and myosin in rat muscle.

作者信息

Shiraki H, Ogawa H, Matsuda Y, Nakagawa H

出版信息

Biochim Biophys Acta. 1979 Feb 9;566(2):335-44. doi: 10.1016/0005-2744(79)90037-8.

Abstract

AMP deaminase was completely solubilized from rat skeletal muscle with 50 mM Tris-HCl buffer (pH 7.0) containing KCl at a concentration of 0.3 M or more. The purified enzyme was found to be bound to rat muscle myosin or actomyosin, but not to F-actin at KCl concentrations of less than 0.3 M. Kinetic analysis indicated that 1 mol of AMP deaminase was bound to 3 mol of myosin and that the dissociation constant (Kd) of this binding was 0.06 micrometer. It was also shown that AMP deaminase from muscle interacted mainly with the light meromyosin portion of the myosin molecule. This finding differs from that of Ashby and coworkers on rabbit muscle AMP deaminase, probably due to a difference in the properties of rat and rabbit muscle AMP deaminase. AMP deaminase isozymes from rat liver, kidney and cardiac muscle did not interact with rat muscle myosin. The physiological significance of this binding of AMP deaminase to myosin is discussed.

摘要

用含有浓度为0.3 M或更高的KCl的50 mM Tris-HCl缓冲液（pH 7.0）可使大鼠骨骼肌中的AMP脱氨酶完全溶解。在KCl浓度低于0.3 M时，发现纯化的酶与大鼠肌肉肌球蛋白或肌动球蛋白结合，但不与F-肌动蛋白结合。动力学分析表明，1摩尔的AMP脱氨酶与3摩尔的肌球蛋白结合，这种结合的解离常数（Kd）为0.06微米。还表明，肌肉中的AMP脱氨酶主要与肌球蛋白分子的轻酶解肌球蛋白部分相互作用。这一发现与阿什比及其同事关于兔肌肉AMP脱氨酶的发现不同，这可能是由于大鼠和兔肌肉AMP脱氨酶的性质不同。来自大鼠肝脏、肾脏和心肌的AMP脱氨酶同工酶不与大鼠肌肉肌球蛋白相互作用。文中讨论了AMP脱氨酶与肌球蛋白这种结合的生理意义。