a protein that, in small amounts, speeds up the rate of a biological reaction without itself being used up in the reaction (i.e. it acts as a catalyst). An enzyme acts by binding with the substance involved in the reaction (the substrate) and converting it into another substance (the product of the reaction). An enzyme is relatively specific in the type of reaction it catalyses; hence there are many different enzymes for the various biochemical reactions. Each enzyme requires certain conditions for optimum activity, particularly correct temperature and pH, the presence of coenzymes, and the absence of specific inhibitors. Enzymes are unstable and are easily inactivated by heat or certain chemicals. They are produced within living cells and may act either within the cell (as in cellular respiration) or outside it (as in digestion). The names of enzymes usually end in ‘-ase’; enzymes are named according to the substrate upon which they act (as in lactase), or the type of reaction they catalyse (as in hydrolase).
Enzymes are essential for the normal functioning and development of the body. Failure in the production or activity of a single enzyme may result in metabolic disorders; such disorders are often inherited and some have serious effects.
enzymatic adj.

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  • Enzyme —   [zu griechisch en »in« und zýmē »Sauerteig«], Singular Enzym das, s, Biokatalysatoren, veraltete Bezeichnung: Fermẹnte, in allen lebenden Organismen vorkommende, intrazellulär gebildete, hochmolekulare Eiweißstoffe (Proteine), die chemische… …   Universal-Lexikon

  • enzyme — [ ɑ̃zim ] n. f. ACAD. ou m. • 1878; gr. en « dans » et zumê « levain » ♦ Biochim. Substance protéique qui catalyse, accélère une réaction biochimique. ⇒ apoenzyme, coenzyme; vx diastase, ferment, zymase. Il existe un grand nombre d enzymes… …   Encyclopédie Universelle

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  • enzyme — en zyme ([e^]n z[imac]m), n. [Pref. en (Gr. en in) + Gr. zy mh leaven.] (Physiol. Chem.) A protein produced by a living organism, capable of catalyzing a chemical reaction. Almost all processes in living organisms require some form of enzyme to… …   The Collaborative International Dictionary of English

  • Enzyme — (griech.), eiweißartige Körper, die fermentartig wirken, in Pflanzen und Tieren weit verbreitet sind und in deren Lebensprozeß eine große Rolle spielen. Über ihre Zusammensetzung ist nichts Sicheres bekannt, über gemeinsame Eigenschaften läßt… …   Meyers Großes Konversations-Lexikon

  • Enzyme — Enzyme, von der Zelle hergestellte Biokatalysatoren, die den Ablauf chemischer Reaktionen beschleunigen, ohne dabei selbst im Endprodukt enthalten zu sein; sind unentbehrlich für sämtliche Stoffwechselvorgänge lebender Organismen, da sie den… …   Deutsch wörterbuch der biologie

  • enzyme — 1881, as a biochemical term, from Ger. Enzym, coined 1878 by German physiologist Wilhelm Kühne (1837 1900), from Modern Gk. enzymos leavened, from en in (see EN (Cf. en ) (2)) + zyme leaven (see ZYMURGY (Cf. zymurgy)) …   Etymology dictionary

  • enzyme — ► NOUN ▪ a substance produced by a living organism and acting as a catalyst to promote a specific biochemical reaction. DERIVATIVES enzymatic adjective enzymic adjective. ORIGIN from modern Greek enzumos leavened …   English terms dictionary

  • enzyme — [en′zīm΄] n. [Ger enzym < LGr enzymos, leavened < Gr en , in + zymē, leaven (see ZYME)] any of various proteins, formed in plant and animal cells or made synthetically, that act as organic catalysts in initiating or speeding up specific… …   English World dictionary

  • Enzyme — Biocatalyst redirects here. For the use of natural catalysts in organic chemistry, see Biocatalysis. Human glyoxalase I. Two zinc ions that are needed for the enzyme to catalyze its reaction are shown as purp …   Wikipedia

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