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