(S)-malate(out) + citrate(in) => (S)-malate(in) + citrate(out)
(s)-malate(out) + citrate(in) => (s)-malate(in) + citrate(out)
(S)-malate(out) + citrate(in) => (S)-malate(in) + citrate(out)
(s)-malate(out) + citrate(in) => (s)-malate(in) + citrate(out)