FIGURE 6.

CcO isolated in the presence of TNFα is inhibited and shows pronounced sigmoidal kinetics. Cow liver tissue was incubated in the presence or absence of TNFα. Mitochondria and subsequently CcO were isolated under conditions that preserve the physiological phosphorylation status (see “Experimental Procedures”). The activity of solubilized CcO pretreated to restore regulatory properties as described (23) was measured in the presence of 5 mm ATP (closed symbols) or ADP (open symbols). Turnover number (TN) is defined as consumed O₂ (μmol)/(s·CcO (μmol)).