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