Polypeptide

Polypeptide
A compound consisting of 2 or more amino acids. Amino acids make up polypeptides which, in turn, make up proteins.
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A peptide formed by the union of an indefinite (usually large) number of amino acid s by peptide links (–NH–CO–).
- gastric inhibitory p. (GIP) a peptide hormone secreted by the stomach; GIP inhibits the secretion of acids and of pepsin and stimulates insulin release as part of the digestive process. SYN: gastric inhibitory peptide.
- glucose-dependent insulinotropic p. an insulinotropic substance originating in the gastrointestinal tract and released into the circulation following ingestion of a meal containing glucose.
- pancreatic p. 1. a 36-amino acid peptide secreted by islet cells of the pancreas in response to a meal and of uncertain physiologic function; 2. a family of gastrointestinal peptides, which includes pancreatic p., neuropeptide Y, and peptide YY.
- trefoil p. a group of polypeptides that share the trefoil moiety of a highly stable three-loop structure held together by disulfide bonds based on cysteine residues; they are widely expressed in gastrointestinal tissues and secreted by mucous cells; their functions are as yet unknown.
- vasoactive intestinal p. (VIP) a p. hormone secreted most commonly by non-β islet cell tumors of the pancreas; VIP increases the rate of glycogenolysis and stimulates pancreatic bicarbonate secretion; excess production causes copious watery diarrhea and fecal electrolyte loss, with hypokalemia and hypochlorhydria. SYN: vasoactive intestinal peptide.

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poly·pep·tide .päl-i-'pep-.tīd n a molecular chain of amino acids
poly·pep·tid·ic -(.)pep-'tid-ik adj

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n.
a molecule consisting of three or more amino acids linked together by peptide bonds. protein molecules are polypeptides.

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poly·pep·tide (pol″e-pepґtīd) [poly- + peptide] a peptide that on hydrolysis yields more than two amino acids; called tripeptides, tetrapeptides, and so on according to the number of amino acids contained. See also peptide.

Medical dictionary. 2011.

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  • polypeptide — [ pɔlipɛptid ] n. m. • 1903; de poly et peptide ♦ Biochim. Substance constituée par la combinaison de plusieurs acides aminés, en nombre supérieur à quatre. Polypeptides naturels, synthétiques. Polypeptides résultant de la digestion des protéines …   Encyclopédie Universelle

  • Polypeptide — ⇒ Peptide …   Deutsch wörterbuch der biologie

  • polypeptide — (n.) peptide built from a large number of amino acids, 1903, from Ger. polypeptid; see POLY (Cf. poly ) + PEPTIDE (Cf. peptide) …   Etymology dictionary

  • polypeptide — [päl΄i pep′tīd΄] n. [ POLY + PEPTIDE] a substance containing two or more amino acids in the molecule joined together by peptide bonds …   English World dictionary

  • Polypeptide — Ein Peptid ist eine organische chemische Verbindung, die aus einer Verknüpfung mehrerer Aminosäuren entstanden ist[1]. Dabei sind die einzelnen Aminosäuren in einer definierten Reihenfolge (Sequenz) zu einer, meist unverzweigten, Kette verbunden …   Deutsch Wikipedia

  • Polypeptide — Un polypeptide est une chaîne de 10 à 100 acides aminés reliés par des liaisons peptidiques. Parmi eux, les peptides multi cycliques, les peptides phosphorylés ou encore ceux intégrant des liaisons non peptidiques ou des peptides conjugués.… …   Wikipédia en Français

  • polypeptide — Chains of a amino acids joined by peptide bonds. Distinction between peptides, oligopeptides and polypeptides is arbitrarily by length; a polypeptide is perhaps more than 10 residues …   Dictionary of molecular biology

  • polypeptide — polipeptidas statusas T sritis chemija apibrėžtis Peptidas, kurio molekulė susideda iš daug α aminorūgščių liekanų. atitikmenys: angl. polypeptide rus. полипептид …   Chemijos terminų aiškinamasis žodynas

  • polypeptide — polipeptidas statusas T sritis augalininkystė apibrėžtis Aminorūgščių, sujungtų peptidiniais ryšiais į linijinę struktūrą, seka. atitikmenys: angl. polypeptide rus. полипептид …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

  • Polypeptide antibiotics — are a class of antibiotics used for eye, ear or bladder infections in addition to aminoglycosides. They are toxic, and are therefore not suitable for systemic administration, but are administered topically on the skin. [… …   Wikipedia

  • Polypeptide N-acetylgalactosaminyltransferase — In enzymology, a polypeptide N acetylgalactosaminyltransferase (EC number|2.4.1.41) is an enzyme that catalyzes the chemical reaction:UDP N acetyl D galactosamine + polypeptide ightleftharpoons UDP + N acetyl D galactosaminyl polypeptideThus, the …   Wikipedia

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