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