Heme b


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
Appearance =
Density =
MeltingPt =
BoilingPt =

Section3 = Chembox Hazards
Solubility =
MainHazards =
FlashPt =
Autoignition =

Heme B is the most abundant heme; both hemoglobin and myoglobin are examples of oxygen transport proteins that contain heme B and the peroxidase family of enzymes also contain heme B. The COX-1 and COX-2 enzymes (cyclooxygenase) of recent fame, also contain heme B at one of two active sites.

Generally, heme B is attached to the surrounding protein matrix (known as the apoprotein) through a single coordination bond between the heme iron and an amino acid side-chain.

Both hemoglobin and myoglobin have a coordination bond to an evolutionary conserved histidine, while Nitric oxide synthase and Cytochrome P450 have a coordination bond to an evolutionary conserved cysteine bound to the iron center of heme B.

Since the iron in heme B containing proteins is bound to the four nitrogens of the porphyrin (forming a plane) and a single electron donating atom of the protein, the iron is often in a pentacoordinate state. When bound with oxygen or the toxin carbon monoxide the iron is hexacoordinated.


Wikimedia Foundation. 2010.

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 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