D-mannose(out) + H(+)(out) = D-mannose(in) + H(+)(in)
d-mannose(out) + h(+)(out) = d-mannose(in) + h(+)(in)
D-mannose(out) + H(+)(out) = D-mannose(in) + H(+)(in)
d-mannose(out) + h(+)(out) = d-mannose(in) + h(+)(in)