Figure 3.

Determination of AOX-sustained respiration (defined as [KCN plus BSA and GTP]-resistant respiration) in state 3 (A) and state 4 (B) in the presence and absence of DTT and pyruvate (Pyr). Mitochondria (mito) were incubated in a standard reaction medium in the presence of 0.5% BSA, 1 mm GTP, and 2 mm ADP (state 3) or 2.5 μg oligomycin mL⁻¹ incubation medium (state 4), as described in Methods; 1.5 mm KCN and 2 mm BHAM were added. The numbers on the traces refer to the O₂-consumption rates in nmol min⁻¹ mg⁻¹ protein. The respiration of green tomato mitochondria is shown as an example. C, CN-resistant respiration (BSA plus GTP) in the absence (•) and presence (▪) of DTT and pyruvate in the four stages of tomato fruit ripeness (G, green; Y, yellow; O, orange; and R, red). The effect of 3.9 μm LA in the presence of DTT and pyruvate (minus BSA minus GTP) is shown (♦). Respiratory rates are in nmol O₂ min⁻¹ mg⁻¹ in states 3 and 4 from four to six independent experiments.