histidine


histidine
α-Amino-β-(4-imidazolyl)propionic acid; the l-isomer is a basic amino acid found in most proteins. It is a nutritionally essential amino acid in mammals.
- h. ammonia-lyase an enzyme catalyzing deamination of l-h. to urocanate and ammonia; this enzyme is absent or deficient in individuals with histidinemia. SYN: histidase, histidinase, h. deaminase.
- h. deaminase SYN: h. ammonia-lyase.
- h. decarboxylase an enzyme catalyzing the pyridoxal-phosphate-dependent decarboxylation of l-h. to histamine and CO2; thus, it plays a role in constriction of bronchial smooth muscle.

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his·ti·dine 'his-tə-.dēn n a crystalline essential amino acid C6H9N3O2 formed by the hydrolysis of most proteins abbr. His

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n.
an amino acid from which histamine is derived.

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his·ti·dine (hisґtĭ-dēn) an essential amino acid, α-amino-1H-imidazole-4-propanoic acid, first found as a decomposition product of the protamine of sturgeon testes; it is obtainable from many proteins by the action of sulfuric acid and water. The decarboxylation of histidine results in the formation of histamine. Symbols His and H. See table at amino acid.

Medical dictionary. 2011.

Look at other dictionaries:

  • Histidine — L ou S( ) histidine D ou R(+) histidine …   Wikipédia en Français

  • histidine — [ istidin ] n. f. • 1897; mot all., de hist(o) , ide et ine ♦ Biochim. L un des vingt acides aminés constituants des protéines, et qui possède un noyau imidazole. ● histidine nom féminin Acide aminé essentiel, composant important de la carnosine… …   Encyclopédie Universelle

  • histidine — histidine. См. гистидин. (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.

  • histidine — complex amino acid, 1896, from Ger. histidin; see HISTO (Cf. histo ) + chemical suffix idine …   Etymology dictionary

  • histidine — [his′ti dēn΄, his′tidin] n. [< Gr histion (see HISTIOCYTE) + INE3] a nonessential amino acid, C3H3N2CH2CH(NH) 2COOH, that is essential for growth in infancy: see AMINO ACID …   English World dictionary

  • Histidine — NatOrganicBox name=2 amino 3 (3H imidazol 4 yl)propanoic acid synonyms=Imidazole alanine PubChem = 773 CAS = 71 00 1 SMILES = N [C@@H] (Cc1 [nH] cnc1)C(O)=O C=6 | H=9 | N=3 | O=2 mass=155.16 g/molHistidine (abbreviated as His or H) [cite web |… …   Wikipedia

  • histidine — /his ti deen , din/, n. Biochem. an essential amino acid, C3H3N2CH2CH(NH2)COOH, that is a constituent of proteins and is important as the iron binding site in hemoglobin. Also, histidin /his ti din/. Abbr.: His; Symbol: H. [1895 1900; HIST + ID3… …   Universalium

  • histidine — histidinas statusas T sritis chemija santrumpa( os) His, H atitikmenys: angl. histidine rus. гистидин ryšiai: sinonimas – 2 amino 3 (1H imidazolil 4 )propano rūgštis …   Chemijos terminų aiškinamasis žodynas

  • histidine — noun Etymology: International Scientific Vocabulary hist + idine Date: 1896 a crystalline essential amino acid C6H9N3O2 formed by the hydrolysis of most proteins …   New Collegiate Dictionary

  • histidine — (= His; H; 155D) An amino acid with an imidazole side chain with a pKa of 6 7. Acts as a proton donor or acceptor and has high potential reactivity and diversity of chemical function. Forms part of the catalytic site of many enzymes …   Dictionary of molecular biology