Figure 4.

Relationship of COX respiratory threshold (COX_T) to relative COX capacity. The data for COX thresholds derived from the COX inhibition data in wild-type 143B and pT3 cells, mutant pT1 and pT4 cells (Fig. 3 and Table 1), and 3 nM rotenone- or 2.7 nM antimycin A-treated 143B cells (Table 1) are plotted against the ratios of (ascorbate + 0.4 mM TMPD)-dependent O₂ consumption rate to endogenous respiration rate (TMPD 0.4 mM/endog. resp.).