Fig. 2.

OGC-mediated transport of its canonical substrates is unaffected by excess GSH. (A) Malate/2-oxoglutarate hetero-exchange in the absence and presence of excess 2-oxoglutarate and GSH. Fused membranes expressing OGC were pre-loaded with 5 mM 2-oxoglutarate and incubated with 1.5 μM [¹⁴C]-malate for 15 min, after which external radio-labelled substrate was removed at the indicated time points (circles). The effects of externally added 10 mM 2-oxoglutarate (squares) or 10 mM GSH (triangles) are shown. (B) Effect of substrates, GSH, GSSG, glutamate and known inhibitors on the initial malate/2-oxoxglutarate exchange rate. The initial exchange rates were calculated from the first 60 s of transport. (C) Malate/malate homo-exchange by OGC in the absence and presence of excess 2-oxoglutarate and GSH. As in A, but the fused membranes were preloaded with 5 mM malate rather than 2-oxoglutarate. (D) Effect of substrates, GSH, GSSG, glutamate and known inhibitors on the initial malate/malate exchange rate of OGC. The initial exchange rates were calculated from the first 60 s of transport. Data are represented by the mean ± S.D. (n = 4). ^∗∗∗P < 0.001, ^∗P < 0.05 for effect of external compound by using ANOVA, or comparison of transport in empty control vesicles and OGC vesicles by Student’s t-test.