pepsin


pepsin
A group of closely related aspartic proteinases. P. A is the principal digestive enzyme of gastric juice, formed from pepsinogen; it hydrolyzes peptide bonds at low pH values (is alkali-labile), preferably adjacent to phenylalanyl and leucyl residues, thus reducing proteins to smaller molecules (referred to as proteoses and peptones); p. B (gelatinase) is similar to p. A, but formed from porcine pepsinogen B and has a more restricted specificity; p. C (gastricsin is human p. C) is also similar to p. A, and structurally related to it, having a more restricted specificity. [G. pepsis, digestion]

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pep·sin 'pep-sən n
1) a crystallizable protease that in an acid medium digests most proteins to polypeptides (as by dissolving coagulated egg albumin or causing casein to precipitate from skim milk), that is secreted by glands in the mucous membrane of the stomach of higher animals, and that in combination with dilute hydrochloric acid is the chief active principle of gastric juice
2) a preparation containing pepsin obtained as a powder or scales from the stomach esp. of the hog and used esp. as a digestant

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n.
an enzyme in the stomach that begins the digestion of proteins by splitting them into peptones (see peptidase). It is produced by the action of hydrochloric acid on pepsinogen, which is secreted by the gastric glands. Once made, pepsin itself can act on pepsinogen to produce more pepsin.

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pep·sin (pepґsin) any of several enzymes of gastric juice that catalyze hydrolysis of proteins to form polypeptides.

Medical dictionary. 2011.

Look at other dictionaries:

  • Pepsin — 3A Pepsin gehemmt durch Pepstatin nach PDB  …   Deutsch Wikipedia

  • pepsin C — pepsin similar to pepsin A but highly active with hemoglobin as substrate. In EC nomenclature called gastricsin …   Medical dictionary

  • Pepsin — Pepsin, den Endopeptidasen (⇒ Proteinasen) zugehörendes, eiweißspaltendes Verdauungsenzym des Wirbeltiermagens, dessen Optimum im pH Bereich zwischen 1,5 und 2,5 liegt. P. wird von den Magenzellen in Form einer inaktiven Vorstufe, dem Pepsinogen …   Deutsch wörterbuch der biologie

  • pepsin — [pep′sin] n. [Ger: coined (1836) by T. Schwann (1810 82), Ger physiologist < Gr pepsis, digestion < peptein, earlier pessein, to cook, digest < IE base * pekw > L coquere,COOK] 1. a digestive enzyme in the gastric juice of stomach… …   English World dictionary

  • Pepsin — Pep sin, n. [Gr. ? a cooking, digesting, digestion, fr. ?, ?, to cook, digest: cf. F. pepsine. Cf. {Dyspepsia}.] (Physiol. Chem.) An unorganized proteolytic ferment or enzyme contained in the secretory glands of the stomach. In the gastric juice… …   The Collaborative International Dictionary of English

  • pepsin — pepsin. См. пепсин. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Pepsin — Pepsin, ein eigenthümliches Ferment im Magensaft, welchem dieser seine verdauende Kraft verdankt; es wirkt in Verbindung mit etwas Säure verdauend auf die Proteïnverbindungen, indem dieselben in die sogenannten Peptone umgewandelt werden. Es ist… …   Pierer's Universal-Lexikon

  • Pepsīn — Pepsīn, fermentartig wirkende Substanz, die von den Labdrüsen der Magenschleimhaut abgesondert wird und bei Anwesenheit von etwas Salzsäure eiweißartige Körper und leimgebende Gewebe nicht nur auflöst, sondern auch in Albumosen und Peptone… …   Meyers Großes Konversations-Lexikon

  • Pepsin — Pepsīn (vom griech. pépsis, Verdauung), das Ferment, das von der Magenschleimhaut ausgesondert wird und bei Anwesenheit von etwas Salzsäure die eiweißartigen Körper auflöst und in Peptone (s.d.) verwandelt; wird künstlich hergestellt durch… …   Kleines Konversations-Lexikon

  • pepsin — also pepsine, fermin in gastric juice, used medicinally for cases of indigestion, 1844, coined in German (1836) from Gk. pepsis “digestion,” from stem pep (see PEPTIC (Cf. peptic)) + IN (Cf. in) (2) …   Etymology dictionary

  • pepsin — pèpsīn m <N mn pepsíni> DEFINICIJA fiziol. ferment želučanog soka, razgrađuje bjelančevine na peptone i time pomaže probavu ETIMOLOGIJA grč. pépsis: kuhanje, vrenje + in …   Hrvatski jezični portal


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