CUSABIO Human opiorphin ELISA kit for you

The major active and less hydrophobic form (18-min retention time) corresponds to the 5 aa residues QRFSR with an experimental molecular mass [determined by surface-enhanced laser desorption ionization–time of flight mass spectrometry (SELDI-TOF MS) analysis] of 690 Da (693-Da theoretical molecular mass). Its molecular characteristics are similar to those of the reference synthetic QRFSR peptide (690 Da), which also presents a second molecular form of 769 Da most likely corresponding to an acetate salt form  Good Human opiorphin ELISA kit http://www.cusabio.com/ELISA-Kit/Human-opiorphin-ELISA-kit-1035168.html  The minor active and more hydrophobic form (26-min retention time) corresponds to two coeluted molecular components, one of 665-Da molecular mass and the second one of 6,493-Da molecular mass. The amino acid determination of the lowest molecular mass was not possible. It may correspond to the cyclization of the N-terminal glutamine residue of the QRFSR peptide to a more hydrophobic pyroglutamic acid active form (GlpRFSR). The highest molecular mass corresponds to a salivary basic proline-rich peptide, P-E (15).

Our data provide direct evidence for the existence of a natural inhibitor of the cell-surface hNEP peptidase, a QRFSR pentapeptide, which is secreted into the human saliva and whose activity is related to the rat sialorphin QHNPR pentapeptide (13) and bovine spinorphin LVVYPWT heptapeptide (7); we named it Opiorphin. Furthermore, it appears that Opiorphin corresponds to the putative mature product of the PRL1 precursor (16). Human PROL1 gene (also known as PRL1 or BPLP gene) is expressed in human salivary glands and belongs to the same multigene family as the sialorphin RATSMR1 precursor (Vcsa1 gene; ref. 11). It encodes a secreted polypeptide, predicted from the cDNA (16), that contains in the N-terminal region a putative peptide QRFSR processed by selective cleavage at consensus sites (recognition sites for signal peptidase and paired basic amino acid convertase). Thus, the combined functional biochemical approach and genomic information give the clues to assign a function to the PROL1 gene product.