D-threo-isocitrate(out) + citrate(in) => D-threo-isocitrate(in) + citrate(out)
d-threo-isocitrate(out) + citrate(in) => d-threo-isocitrate(in) + citrate(out)
D-threo-isocitrate(out) + citrate(in) => D-threo-isocitrate(in) + citrate(out)
d-threo-isocitrate(out) + citrate(in) => d-threo-isocitrate(in) + citrate(out)