methionine

2-Amino-4-(methylthio)butyric acid; the l-isomer is a nutritionally essential amino acid and the most important natural source of “active methyl” groups in the body, hence usually involved in methylations in vivo; the dl-form is used as an adjunct in the treatment of liver diseases.
- active m. SYN: S-adenosyl-l-m..
- m. adenosyltransferase an enzyme catalyzing the condensation of l-m. and ATP, forming S-adenosyl-l-m., orthophosphate, and pyrophosphate; a deficiency of the hepatic enzyme will result in hypermethionemia. SYN: m.-activating enzyme.
- m. sulfoxime a toxic derivative of m. formed when proteins containing it are treated with nitrogen chloride to give –SO(NH)CH3 in place of –SCH3.
- m. synthase tetrahydropteroylglutamate methyltransferase; m.-homocysteine methyltransferase; an enzyme that catalyzes the reaction of N5-methyltetrahydrofolate with l-homocysteine to form tetrahydrofolate and l-m.; a cobalamin-requiring enzyme; a deficiency of this enzyme results in an accumulation of l-homocysteine and neurological abnormalities. SYN: tetrahydrofolate methyltransferase.

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me·thi·o·nine mə-'thī-ə-.nēn n a crystalline sulfur-containing essential amino acid C5H11NO2S that occurs in the L-form as a constituent of many proteins (as casein and egg albumin), that is important esp. as a source of sulfur for the biosynthesis of cysteine and as a source of methyl groups for transmethylation reactions (as in the biosynthesis of choline, creatine, and adrenaline), and that is used as a dietary supplement for human beings and their domestic mammals and poultry and in the treatment of fatty infiltration of the liver abbr. Met

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n.
a sulphur-containing essential amino acid. See also amino acid.

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me·thi·o·nine (Met) (M) (mə-thiґo-nēn) chemical name: α-amino-γ-methylmercaptobutyric acid; a naturally occurring essential amino acid furnishing both methyl groups and sulfur necessary for normal metabolism. See also table at amino acid. [USP] a preparation of methionine used as a dietary supplement.

Medical dictionary. 2011.

Look at other dictionaries:

  • Methionine — Methionine …   Wikipedia

  • Méthionine — L ou S méthionine D ou R méthionine …   Wikipédia en Français

  • Methionine — Méthionine Méthionine Général …   Wikipédia en Français

  • méthionine — [ metjɔnin ] n. f. • 1949; angl. methionine (1928); cf. méthyle et thio ♦ Biochim. Acide aminé essentiel soufré, qui joue un rôle fondamental dans la traduction de l A. R. N. messager et dans les transferts biologiques de groupements méthyles. ●… …   Encyclopédie Universelle

  • methionine — methionine. См. метионин. (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.

  • methionine — [mə thī′ə nēn΄, mə thī′ənin] n. [ ME(THYL) + THION(IC) + INE3] an essential amino acid, CH3SCH2CH2CH(NH2)COOH, that contains sulfur, obtained from various proteins and used as a food supplement and in medicine …   English World dictionary

  • methionine — /me thuy euh neen , nin/, n. Biochem. an amino acid, CH3SCH2CH2CH(NH2)COOH, found in casein, wool, and other proteins or prepared synthetically: used as a supplement to a special diet in the prevention and treatment of certain liver diseases.… …   Universalium

  • methionine — (= met; M; 149D) Contains the SCH3 group that can act as a methyl donor (see S adenosyl methionine). Common in proteins but at low frequency. The met x linkage is subject to specific cleavage by cyanogen bromide. See also formyl peptides …   Dictionary of molecular biology

  • methionine C 11 — [USP] L methionine in which a portion of the molecules have been labeled with carbon 11, used as a tracer in positron emission tomography for the detection of malignant neoplasms; administered intravenously …   Medical dictionary

  • methionine — metioninas statusas T sritis chemija formulė CH₃SCH₂CH₂CH(NH₂)COOH santrumpa( os) Met, M atitikmenys: angl. methionine rus. метионин ryšiai: sinonimas – 2 amino 4 metiltiobutano rūgštis …   Chemijos terminų aiškinamasis žodynas

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