Figure 5. The self-exchange reaction of Q and QH₂ in the presence of inhibited complex I.

Different species of Q and QH₂ were incubated together in the assay buffer at 30 °C, in the presence of complex I, phospholipids, NADH and either rotenone or piericidin A, and their self-exchange reaction was monitored over time by HPLC analysis (◆, DQ; ■, Q₂; ◇, DQH₂; □, Q₂H₂). (A) DQ and Q₂H₂ in the presence of complex I inhibited by piericidin A (bovine phospholipids) modelled using k₁=52 mol⁻¹·dm³·s⁻¹ (inhibitor-insensitive catalysis, k₂=17 mol⁻¹·dm³·s⁻¹). (B) DQH₂ and Q₂ incubated in the presence of complex I inhibited by rotenone (asolectin) modelled using k₁=65 mol⁻¹·dm³·s⁻¹ (inhibitor-insensitive catalysis, k₂=44 mol⁻¹·dm³·s⁻¹). (C) DQH₂ and Q₂ incubated in the presence of complex I inhibited by piericidin A (asolectin) modelled using k₁=77 mol⁻¹·dm³·s⁻¹ (inhibitor-insensitive catalysis, k₂=33 mol⁻¹·dm³·s⁻¹).