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Pancreatic Polypeptide Family: Peptide YY and Neuropeptide Y

المؤلف:  Norman, A. W., & Henry, H. L.

المصدر:  Hormones

الجزء والصفحة:  3rd edition , p157

2026-07-08

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All three members of the pancreatic polypeptide (PP) family have the same number of 36 amino acids and have an amidated C-terminal tyrosine residue; see Figure 1A. Pancreatic polypeptide is colored blue, peptide YY (PYY) is colored purple, and neuropeptide Y (NPY) is colored green; each of the 36 amino acid residues of pancreatic polypeptide were separately compared with the 36 residues of PYY and NPY. All exact matches were colored gold. Also the amino acid sequences of PYY and NPY were compared and all identical amino acid identities were also colored gold. These matches may reflect evolutionary changes in the order of amino acids. PP has 13 of its 36 amino acids identical to PYY and 15 of its 36 amino acids identical to NPY. PYY has 17 of its 36 amino acids identical to NPY. PP is secreted by pancreatic islet cells (see Figure 1) and its receptor is present in the small intestine, colon, and the pancreas. Peptide YY function ally is an enterogastrone, which describes any hormone secreted by the mucosa of the duodenum as a response to food intake. Neuropeptide Y (NPY) is widespread in the peripheral and central nervous systems and also has important inhibitory actions in the intestinal tract.

Fig1. Amino acid sequence comparison of the pancreatic polypeptide hormone family. These include pancreatic polypeptide (PP), peptide tyrosine tyrosine (PYY), and neuropeptide tyrosine (NPY). (A) The 36 amino acids of each of the hormones are colored differently; PP is blue, PYY is purple, and NPY is green. The three peptides were aligned on the basis of each of the NH2-terminus residues being assigned #1 and the carboxy amide being numbered 36. Each of the 36 amino acid residues of PP was separately compared with the 36 residues of PYY and NPY. All exact matches with PP were colored gold. Also, the amino acid sequences of PYY and NPY were compared and all identical amino acid identities were also colored gold. These matches may reflect evolutionary changes in the order of amino acids. (B) Illustration of the pancreatic polypeptide fold as determined via x-ray crystallography and also NMR. The PP fold is comprised of residues #3 to #31 of the 36 amino acid peptide. The formation of the “fold” is believed to be facilitated by the four proline residues at peptide positions #2, #5, #8, and #14.

The three-dimensional structure of each of the three members of the pancreatic polypeptide family of hormones includes a hairpin-like motif known as the pancreatic polypeptide fold (PP fold), illustrated in Figure 1B as determined via X-ray crystallography and also NMR. The PP fold is comprised of residues #3 to #31 of the 36 amino acid peptide. The formation of the “fold” is believed to be facilitated by the four proline residues at peptide positions #2, #5, #8, and #14. It has been proposed that the tightly organized tertiary structure of the PP fold is required for interaction of the PP family member hormones with their specific cognate G-protein coupled receptors.