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