A Biophysical Mechanism for Muscle Contraction and Spontaneous Oscillation
Based on a simplified model of mechanochemical actin-activated myosin ATPase cycle the muscle state equation and muscle kinetic equation are deduced from the biochemical thermodynamic principles. A set of chemical kinetic equations describing the cycle is established. From the non-equilibrium steady state solution of the set of equations, the experimental data on the fraction of myosin heads in any biochemical state independent of the concentration of inorganic phosphate, Pi, and the data on the active, isometric muscle force varying logarithmically with Pi are explained. Therefore, how force as a state variable coupled to chemical reaction in muscle system is clarified and the muscle state equation is set up. Based on the muscle state equation, by use of the worm-like chain fits on the force versus extension characteristic of elastic elements in muscle and taking the viscous frictional force into account, a kinetic equation for sarcomeres is given and through the solution of the equation, both contraction and spontaneous oscillation of sarcomeres are explained in a natural way. The computational results agree well with experimental data. In the last section of the paper the implications relating to the possibly existed power stroke in the actin-myosin system are explored briefly in terms of the proposed simplified model on actomyosin ATPase cycle.
myosin ATPase cycle chemical kinetic equations sarcomeres contraction and oscillation kinetic equation power stroke
Weisheng Guo
Department of Physics, College of Sciences and Technology, Inner Mongolia University, Hohhot 010021 China
国际会议
上海
英文
1955-1961
2011-10-15（万方平台首次上网日期，不代表论文的发表时间）