preferred_name: Mg(2+)(out) + 2 Na(+)(in) => Mg(2+)(in) + 2 Na(+)(out)
preferred_name_lc: mg(2+)(out) + 2 na(+)(in) => mg(2+)(in) + 2 na(+)(out)
label: Mg(2+)(out) + 2 Na(+)(in) => Mg(2+)(in) + 2 Na(+)(out)
label_lc: mg(2+)(out) + 2 na(+)(in) => mg(2+)(in) + 2 na(+)(out)