Ca(2+)(out) + n H(+)(in) => Ca(2+)(in) + n H(+)(out)
ca(2+)(out) + n h(+)(in) => ca(2+)(in) + n h(+)(out)
Ca(2+)(out) + n H(+)(in) => Ca(2+)(in) + n H(+)(out)
ca(2+)(out) + n h(+)(in) => ca(2+)(in) + n h(+)(out)