preferred_name: melibiose(in) + Na(+)(in) => melibiose(out) + Na(+)(out)
preferred_name_lc: melibiose(in) + na(+)(in) => melibiose(out) + na(+)(out)
label: melibiose(in) + Na(+)(in) => melibiose(out) + Na(+)(out)
label_lc: melibiose(in) + na(+)(in) => melibiose(out) + na(+)(out)