 It works by stopping the normal breakup of enkephalins, natural pain-killing opioids in the spinal cord.It is a relatively simple molecule consisting of a five-amino acid polypeptide, Gln-Arg-Phe-Ser-Arg.Opiorphin pentapeptide originates from the N-terminal region of the protein PROL1 (proline-rich, lacrimal 1).