cholate(out) + n H(+)(out) => cholate(in) + n H(+)(in)
cholate(out) + n h(+)(out) => cholate(in) + n h(+)(in)
cholate(out) + n H(+)(out) => cholate(in) + n H(+)(in)
cholate(out) + n h(+)(out) => cholate(in) + n h(+)(in)