heme

1. The porphyrin chelate of iron in which the iron is Fe(II) (or Fe2+); the oxygen-carrying, color-furnishing, prosthetic group of hemoglobin. 2. Iron complexed with nonporphyrins but related tetrapyrrole structures ( e.g., biliverdin h.). 3. Iron chelated with any porphyrin, irrespective of the valence state of the iron atom. SYN: ferroheme, ferroprotoporphyrin, reduced hematin. [G. haima, blood]
- h. a a derivative of h. found in cytochrome aa3.
- h. c a derivative of h. found in cytochromes c, b4, and f.

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heme or chiefly Brit haem 'hēm n the deep red iron-containing prosthetic group C34H32N4O4Fe of hemoglobin and myoglobin that is a ferrous derivative of protoporphyrin and readily oxidizes to hematin or hemin called also protoheme

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(hēm) 1. any quadridentate chelate of iron with the four pyrrole groups of a porphyrin, further distinguished as ferroheme or ferriheme referring to the chelates of Fe(II) and Fe(III) respectively. The four porphyrin ligands form a square-planar complex; the fifth and sixth coordination positions of the iron atom are perpendicular to the plane of the porphyrin and both may be occupied by strong field ligands, such as a nitrogen atom of a histidine residue of a protein, as in cytochromes, or only one may be so occupied, as in hemoglobin where the sixth position reversibly binds oxygen. 2. ferroheme. 3. protoheme IX, the heme of hemoglobin. See protoheme.

Medical dictionary. 2011.

Look at other dictionaries:

  • Heme — Hème Hème de type b Un hème est un cofacteur contenant un atome de fer servant à accueillir un gaz diatomique (souvent le dioxygène O2) au centre d’un large anneau organique appelé porphyrine. Toutes les porphyrines ne contiennent pas… …   Wikipédia en Français

  • Hème — de type b Représentation 3D Un hème est un cof …   Wikipédia en Français

  • hème — [ ɛm ] n. m. • 1970; du gr. haima « sang » ♦ Biochim. Pigment contenant du fer ferreux et constituant la partie prosthétique de certaines protéines telles que l hémoglobine. ● hème nom masculin Composé ferreux dérivé de l hématoporphyrine qui… …   Encyclopédie Universelle

  • heme — heme; pro·to·heme; …   English syllables

  • heme — heme. См. гем. (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.

  • heme — Síntesis de la partícula demostrativa «he» y el acusativo del pronombre de primera persona. ⇒ He …   Enciclopedia Universal

  • heme —  Heme  Гем   Небелковая часть молекулы гемоглобина. Содержит в молекуле комплекс порфирина с Fe2+. Легко окисляется на воздухе до гематина, имеющего ту же структуру, но содержащего Fe3+. Обусловливает цвет крови, является переносчиком кислорода в …   Толковый англо-русский словарь по нанотехнологии. - М.

  • heme — [hēm] n. [contr. < HEMATIN] the nonprotein, iron containing pigment, C34H32N4O4Fe, that is a component part of hemoglobin, myoglobin, etc …   English World dictionary

  • Heme — A heme (American English) or haem (British English) is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin . Not all porphyrins contain iron, but a substantial fraction… …   Wikipedia

  • Heme b — Chembox new ImageFile = Heme.svg ImageSize = IUPACName = OtherNames = Section1 = Chembox Identifiers CASNo = 14875 96 8 PubChem = 444098 SMILES = MeSHName = Heme+b Section2 = Chembox Properties Formula = C34H32O4N4Fe MolarMass = 616.487… …   Wikipedia

  • Heme c — Chembox new ImageFile = Heme c.svg ImageSize = 250px IUPACName = OtherNames = Section1 = Chembox Identifiers CASNo = 26598 29 8 PubChem = 444125 SMILES = MeSHName = heme+C Section2 = Chembox Properties Formula = C34H36O4N4S2Fe MolarMass = 684.651 …   Wikipedia

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