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