Figure 6.

Model fits to data from isolated muscle preparations. Predictions of the model for the effect of P_i on myofibrils and muscle fibers. (Left) Effect of phosphate on isometric force at 4 mM ATP. The model and data are both normalized to the Hill fit of force-velocity at 0 mM P_i. Data are for rabbit psoas myofibrils (10) and are qualitatively similar to the model. (Right) Effect of phosphate on isometric ATPase (24,25). Again, the data are qualitatively similar to the model. Note that these are not fits to the data but rather predictions of the model. (Note that the data are rescaled to have an ATPase in the absence of P_i of 20 s⁻¹.)