A, Correlation between ATP levels and CT-L proteasome peptidase activities in heart (open squares), lung (light grey squares), and pectoral muscle (dark grey squares) extracts. Data from Figure 1B and C. r2 = 0.89. B, CT-L proteasome peptidase activities (pmol/min/50 µg) in normal heart (open squares), lung (dark grey squares), and pectoral muscle (dark grey squares) extracts measured at various ATP concentrations. Data are presented as mean (SD), n = 3 to 5. C, Correlation between assay ATP concentrations and CT-L proteasome peptidase activities. Data from B. Peptidase activities measured at 2mM (lung and pectoral muscle) and 5mM (heart) ATP were considered to equal 100%. r2 = 0.82 to 0.96.