Skip to main content
. Author manuscript; available in PMC: 2008 Jan 1.
Published in final edited form as: J Mol Cell Cardiol. 2006 Nov 30;42(1):265–269. doi: 10.1016/j.yjmcc.2006.10.010

Figure 1. Optimal conditions for determination of cardiac 26S-proteasome activity. Panel A: The effect of ATP concentration.

Figure 1

Aliquots (30 μg protein) of rat heart tissue cytosol was assayed for chymotrypsin-like and caspase-like activities in the presence of increasing concentrations of ATP. The inset shows the data normalized to the 0 μmol/L ATP or basal activity to determine magnitude of activation. The values represent the mean ± SEM of 5 to 7 determinations. Panel B: The effect of increasing protein concentrations. Aliquots of rat heart tissue cytosol containing up to 90 μg protein were assayed for chymotrypsin-like and caspase-like activities in the presence of increasing concentrations of ATP. The values represent the mean of 2 to 3 determinations. Panel C: The effect of proteasome inhibitors. Aliquots (30 μg protein) of rat heart tissue cytosol was assayed for chymotrypsin-like and caspase-like activities at the optimal ATP concentration of 28 μmol/L and in the presence of increasing concentrations of the proteasome inhibitors, lactacystin (Lac) and Z-Pro-Nle-Asp-CHO (ZPNAC). The inset shows the effect of increasing ATP concentrations on chymotrypsin-like activity in the absence and presence of Lac, 10 μmol/L. The values represent the mean of 2 to 3 determinations.