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