preferred_name: citrate(out) + succinate(in) <=> citrate(in) + succinate(out)
preferred_name_lc: citrate(out) + succinate(in) <=> citrate(in) + succinate(out)
label: citrate(out) + succinate(in) <=> citrate(in) + succinate(out)
label_lc: citrate(out) + succinate(in) <=> citrate(in) + succinate(out)