Figure 6.

Myofibril ATPase assay. ATPase activity of bovine cardiac myofibrils (top) and rabbit skeletal myofibrils (bottom) were measured in the presence of 1% DMSO and 50 μM compound across a 12-point Ca²⁺ gradient, pCa 4 to 8, in a 96-well–plate. Error bars are SD (N = 3, n = 6 at each Ca²⁺ concentration). ATPase activity was calculated as a micromole of ATP/mg of protein/min scale. Graphs are normalized to the DMSO-only sample for better visualization of the compound effect on cardiac and skeletal. Calculated ATPase rates at pCa 4 and at pCa 8 are summarized in Table 4.