肌肉自发振动过程中结合几率与化学反应速率的变化

Change of the Binding Probability and Chemical Reaction Rate in Spontaneous Oscillatory Contraction of Muscles

定量分析肌球蛋白与肌动蛋白丝的结合几率及相关化学反应的速率常数,对于准确掌握肌肉收缩的内在机制具有非常重要的意义.以肌肉自发振动的实验结果为依据,从振动过程所满足的动力学方程出发,推导出结合几率与肌丝滑行速度及肌节长度之间的定量关系,并求得化学反应速率随肌肉收缩的速度变化而改变的数学规律.结果显示,结合几率的基准值由溶液中主要化学成分的浓度决定;结合几率的变化值与肌肉收缩的速度成正比,与肌节长度成反比;而化学反应速率随收缩速度按指数规律变化.上述结果与实验值基本一致.

Quantitative analysis of the binding probability of myosin and actin filament and its related chemical reaction rate constants is very important to understand the intrinsic mechanism of muscle contraction. Based on the experiment results of spontaneous oscillatory contraction of muscles（SPOC）, the quantitative relationship of the binding probability to the concentration of solution, sarcomere length and the sliding speed of actin filaments are deduced from the kinetic equation describing SPOC. Mathematical law reflected the change of the chemical reaction rate with the muscle contraction velocity is established also. The results show the follow three conclusions：one is that the baseline value of the binding probability is determined by the concentration of the main chemical components in the solution, the second is that the binding probability is directly proportional to the sliding speed and inversely proportional to the sarcomere length,and the third is that the chemical reaction rate is exponentially related to the contraction speed. These conclusions are in agreement with the experimental results.