Figure 3. Effect of HNE on the tomato Aox isoforms LeAox1a and LeAox1b.

Mitochondria were isolated from yeast expressing either LeAox1a (■) or LeAox1b (◆), suspended in reaction medium and incubated with various concentrations of HNE (0–200 μM) for 10 min. Respiration was initiated by the addition of 2 mM NADH and 1 mM ADP. Electron transport via Aox was measured in the presence of 2.5 μM myxothiazol to inhibit the cytochrome pathway, 2.5 mM DTT, and either 10 mM pyruvate (LeAox1a) or 10 mM succinate (LeAox1b), to ensure activation of Aox. Addition of 0.5 mM n-PG inhibited respiration completely. The control rate of oxygen uptake via Aox was 70 nmol·min⁻¹·mg⁻¹ of protein in both cases.