| 词条 | Heme B |
| 释义 |
| verifiedrevid = 396492132 | ImageFile = Heme b.svg | ImageSize = 150px | ImageAlt = Skeletal formula of heme B | ImageFile1 = Heme B 3D spacefill.png | ImageSize1 = 170 | ImageAlt1 = Space-filling model of the heme B complex | IUPACName = | OtherNames = Iron protoporphyrin IX, protoheme IX |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 16739950 | InChI = 1/C34H34N4O4.Fe/c1-7-21-17(3)25-13-26-19(5)23(9-11-33(39)40)31(37-26)16-32-24(10-12-34(41)42)20(6)28(38-32)15-30-22(8-2)18(4)27(36-30)14-29(21)35-25;/h7-8,13-16H,1-2,9-12H2,3-6H3,(H4,35,36,37,38,39,40,41,42);/q;+2/p-2/b25-13-,26-13-,27-14-,28-15-,29-14-,30-15-,31-16-,32-16-;/rC34H32FeN4O4/c1-7-21-17(3)25-13-29-20(6)24(10-12-34(42)43)32-16-28-23(9-11-33(40)41)18(4)26(37-28)14-31-22(8-2)19(5)30(15-27(21)36-25)38(31)35-39(29)32/h7-8,13-16H,1-2,9-12H2,3-6H3,(H,40,41)(H,42,43)/b25-13-,26-14-,27-15-,28-16-,29-13-,30-15-,31-14-,32-16- | InChIKey = KABFMIBPWCXCRK-SMDPYJEOBB | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C34H34N4O4.Fe/c1-7-21-17(3)25-13-26-19(5)23(9-11-33(39)40)31(37-26)16-32-24(10-12-34(41)42)20(6)28(38-32)15-30-22(8-2)18(4)27(36-30)14-29(21)35-25;/h7-8,13-16H,1-2,9-12H2,3-6H3,(H4,35,36,37,38,39,40,41,42);/q;+2/p-2/b25-13-,26-13-,27-14-,28-15-,29-14-,30-15-,31-16-,32-16-; | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = KABFMIBPWCXCRK-RGGAHWMASA-L | CASNo_Ref = {{cascite|correct|CAS}} | CASNo = 14875-96-8 | PubChem = 444098 | SMILES = OC(=O)CC/C6=C(\\C)/C=3/N=C6/C=C2/C(/CCC(O)=O)=C(/C)\\C1=C\\C5=N\\C(=C/c4n([Fe]N12)c(C=3)c(C=C)c4C)C(\\C=C)=C5\\C | MeSHName = Heme+b | SMILES1 = OC(=O)CC/c6c(\\C)c3n7c6cc2c(/CCC(O)=O)c(/C)c1cc5n8c(cc4n([Fe]78n12)c(c=3)c(C=C)c4c)c(\\C=C)c5\\C |Section2={{Chembox Properties | Formula = C34H32O4N4Fe | MolarMass = 616.487 | Appearance = | Density = | MeltingPt = | BoilingPt = |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} Heme B or haem B (also known as protoheme IX) is the most abundant heme.{{fact|date=December 2018}} Hemoglobin and myoglobin are examples of oxygen transport proteins that contain heme B. 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 evolutionarily-conserved histidine, while nitric oxide synthase and cytochrome P450 have a coordination bond to an evolutionarily-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 oxygen or the toxic carbon monoxide is bound the iron becomes hexacoordinated. The correct structures of heme B and heme S were first elucidated by German chemist Hans Fischer.[1] {{Enzyme cofactors}}{{tetrapyrroles}}References1. ^{{cite book | last1 = Fischer|first1=H. | last2 = Orth|first2=H. | title =Die Chemie des Pyrrols | location = Liepzig | publisher = Akademische Verlagsgesellschaft | date =1934 }} 2 : Tetrapyrroles|Biomolecules |
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