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