melibiose(out) + H(+)(out) => melibiose(in) + H(+)(in)
melibiose(out) + h(+)(out) => melibiose(in) + h(+)(in)
melibiose(out) + H(+)(out) => melibiose(in) + H(+)(in)
melibiose(out) + h(+)(out) => melibiose(in) + h(+)(in)