4-hydroxybenzoate(out) + H(+)(in) => 4-hydroxybenzoate(in) + H(+)(out)
4-hydroxybenzoate(out) + h(+)(in) => 4-hydroxybenzoate(in) + h(+)(out)
4-hydroxybenzoate(out) + H(+)(in) => 4-hydroxybenzoate(in) + H(+)(out)
4-hydroxybenzoate(out) + h(+)(in) => 4-hydroxybenzoate(in) + h(+)(out)