ATPase in muscle

Figure 9.20 The creatine/phosphocreatine shuttle between subsarcolemmal mitochondria and myosin ATPase in muscle. The distance between the mitochondria that reside just below the plasma membrane (sarcolemma) and the myofibrils in which the myosin ATPase results in contraction, is long in such muscles. The advantage of the position of these mitochondria is ready access to oxygen and fuel from blood. Such mitochondria are common in endurance athletes.

Goldman YE (1987) Kinetics of the actomyosin ATPase in muscle fibers. Annu Rev Physiol 49 637-654... 

This approach resolves the difficulty created by the hypothesis of direct energy transduction from the chemical to mechanical form. As in the case of membrane transport energized by H ATPases, in muscles also there is first a buildup of a proton-motive force across the lengths of the myofilaments with the electroosmotic flow of the cationic layer converting it to the mechanical output. 

---