urate(out) + (S)-lactate(in) = urate(in) + (S)-lactate(out)
urate(out) + (s)-lactate(in) = urate(in) + (s)-lactate(out)
urate(out) + (S)-lactate(in) = urate(in) + (S)-lactate(out)
urate(out) + (s)-lactate(in) = urate(in) + (s)-lactate(out)