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. Author manuscript; available in PMC: 2013 Oct 25.
Published in final edited form as: J Phys Chem B. 2011 Feb 18;115(10):10.1021/jp1094504. doi: 10.1021/jp1094504

Figure 7.

Figure 7

Bepridil enhances ATPase activity at low free calcium concentrations. The ratio of rate of ATP hydrolysis (with bepridil/without bepridil) is shown with standard deviations as a function of the pCa. The bepridil concentration is 125 μM with 1% ethanol as a carrier. Conditions: 25° C with 0.1 μM S1, 20 μM actin, 5.7 μM tropomyosin and 5.7 μM troponin. The reaction buffer contained 1 mM ATP, 3 mM MgCl2, 20 mM MOPS pH 7, 1mM dithiothreitol and sufficient CaCl2 and EGTA to reach the target pCa. The ionic strength was adjusted to 62 mM by the addition of KCl. Values in the presence of bepridil were multiplied by 1.23 to correct for inhibition of actin-tropomyosin stimulated ATPase activity by bepridil.