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