guanosine(in) + H(+)(out) = guanosine(out) + H(+)(in)
guanosine(in) + h(+)(out) = guanosine(out) + h(+)(in)
guanosine(in) + H(+)(out) = guanosine(out) + H(+)(in)
guanosine(in) + h(+)(out) = guanosine(out) + h(+)(in)