Fig. 5. Rates of oxygen consumption and ${\mathbf{O}}_{\mathbf{2}}^{\overline{·}}$ generation in CoQ-depleted/reconstituted bovine heart SMPs.

Freeze-dried SMPs were depleted of native CoQ by six repeated extractions with pentane and reconstituted with specific amounts of CoQ homologues as described in Fig. 4, and the rates of ${\text{O}}_2^{\overline{·}}$ generation, shown in A, were measured. Plot B shows the rates of succinate-supplemented oxygen consumption of the SMPs from the same set of experiments. The insets depict the relationship between rates of ${\text{O}}_2^{\overline{·}}$ generation and oxygen consumption by SMPs and CoQ concentrations, within the physiological range. Data are mean ± S.E. of three independent experiments; S.E. is not shown in the inset.