Figure 1

Oxidizing NAD-linked substrates in the absence of phosphate leads to a decreased respiratory rate. panel A, the medium contained 0.6 M mannitol, 10 mM HEPES (TEA⁺), pH 7.20. Where indicated 10 mM KP_i was present. At 1.25 min. 4 mM ethanol, 0.5 mM NADH, or 5 mM succinate (K⁺), or a combination of 4 mM pyruvate (Na⁺), 4 mM malate (K⁺) and 4 mM glutamate (K⁺) were added. These concentrations were chosen to give moderate and fairly comparable rates of respiration. panel B, the conditions were the same as panel A except 32 mM ethanol was added instead of 4 mM ethanol.