FIGURE 1.
Force-pCa curves of skinned porcine papillary muscle utilizing 100% ATP (solid circles) or 100% dATP (open triangles) as the contractile substrate. Active force was normalized to Fmax (pCa 4.5) for ATP in the same fiber bundle (n = 7). Lines are nonlinear least-squares regression fits to the Hill equation (Eq. 1). There were no differences in parameter estimates of pCa50 or nH between ATP versus dATP.