Isolation and characterization of peptide YY (PYY), a candidate gut hormone that inhibits pancreatic exocrine secretion

A new candidate hormone--designated peptide YY (PYY)--has been isolated from extracts of porcine upper intestinal tissue by using a novel chemical assay method. This peptide has been detected in the extracts by the presence of its unusual COOH-terminal tyrosine amide structure. The peptide consists of a linear chain of 36 Amino acids and its complete amino acid sequence is: Tyr-Pro-Ala-Lys-Pro-Glu-Ala-Pro-Gly-Glu-Asp-Ala-Ser-Pro-Glu-Glu-Leu-Ser-Arg-Tyr -Tyr-Ala-Ser-Leu-Arg-His-Tyr-Leu-Asn-Leu-Val-Thr-Arg-Gln-Arg-Tyr-NH2. This peptide has a distinct sequence homology to the pancreatic polypeptide. It is therefore proposed that PYY and the pancreatic polypeptide together form a new peptide family. PYY has been found to strongly inhibit both secretin- and cholecystokinin-stimulated pancreatic secretion in the anesthetized cat.