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