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MetaCyc Compound: ferroheme b

Synonyms: protoheme IX, ferroprotoporphyrin IX

Superclasses: a macrocycle a porphyrin heme heme b
an organometallic compound heme b

Summary:
'Heme' is usually understood as any tetrapyrrolic chelate of iron. The terms 'ferroheme' and 'ferriheme' refer to the Fe(II) and Fe(III) oxidation states in heme (even though Fe(IV) is found as a catalytic intermediate in some systems).

Heme b, whose ferrous form is known as protoheme IX, is the immediate product of the heme biosynthesis pathways (by ferro-chelation of protoporphyrin IX) and the most abundant heme form. It is found in common proteins such as hemoglobin and myoglobin.

Heme b is part of b-type cytochromes.

Chemical Formula: C34H30N4O4Fe

Molecular Weight: 614.48 Daltons

Monoisotopic Molecular Weight: 616.1772976364 Daltons

SMILES: C=CC1(C(C)=C7(C=C8(C(C)=C(CCC(=O)[O-])C6(=[N+]([Fe--]24(N(C=1C=C3(C(C)=C(C=C)C(=[N+]23)C=C5(C(C)=C(CCC(=O)[O-])C(N45)=C6)))7))8))))

InChI: InChI=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-4/b25-13-,26-13-,27-14-,28-15-,29-14-,30-15-,31-16-,32-16-;

InChIKey: InChIKey=KABFMIBPWCXCRK-RGGAHWMASA-J

Standard Gibbs Free Energy of Change Formation (ΔfG in kcal/mol): 277.38635 Inferred by computational analysis [Latendresse13]

Reactions known to consume the compound:

heme degradation , phycocyanobilin biosynthesis , phycoerythrobilin biosynthesis , phytochromobilin biosynthesis :
ferroheme b + 3 a reduced electron acceptor + 3 oxygen + 2 H+ → biliverdin-IX-α + Fe2+ + carbon monoxide + 3 an oxidized electron acceptor + 3 H2O

Not in pathways:
ferroheme b + 4 a reduced electron acceptor + 4 oxygen + 2 H+ → 5-oxo-δ-bilirubin + Fe2+ + carbon monoxide + 4 an oxidized electron acceptor + 4 H2O
ferroheme b + 4 a reduced electron acceptor + 4 oxygen + 2 H+ → 15-oxo-β-bilirubin + Fe2+ + carbon monoxide + 4 an oxidized electron acceptor + 4 H2O

Reactions known to produce the compound:

heme biosynthesis I (aerobic) , heme biosynthesis II (anaerobic) , superpathway of heme biosynthesis from uroporphyrinogen-III :
protoporphyrin IX + Fe2+ferroheme b + 2 H+

heme biosynthesis III (from siroheme) :
Fe-coproporphyrin III + 2 S-adenosyl-L-methionine → ferroheme b + 2 CO2 + 2 5'-deoxyadenosine + 2 L-methionine

Reactions known to both consume and produce the compound:

Not in pathways:
heme b + (2E,6E)-farnesyl diphosphate + H2O ↔ heme o + diphosphate

In Reactions of unknown directionality:

Not in pathways:
heme b + hydrogen peroxide = heme d

In Transport reactions:
heme b[cytosol] + ATP + H2O → heme b[periplasmic space] + ADP + phosphate + H+ ,
heme b[cytosol] + ATP + H2O ↔ heme b[periplasmic space] + ADP + phosphate + H+

Enzymes inhibited by ferroheme b, sorted by the type of inhibition, are:

Inhibitor (Noncompetitive) of: 5-aminolevulinate synthase [Burnham63, Jordan86]

Inhibitor (Mechanism unknown) of: ferrochelatase [Dailey86]

This compound has been characterized as a cofactor or prosthetic group of the following enzymes: succinate:quinone oxidoreductase , cytochrome bo terminal oxidase , cytochrome bd-I terminal oxidase , dihydropteridine reductase , nitric oxide dioxygenase , hydroperoxidase , catalase

Credits:
Created 21-Aug-2014 by Caspi R , SRI International


References

Burnham63: Burnham B. F., Lascelles J. (1963). "Control of porphyrin biosynthesis through a negative-feedback mechanism." Biochem. J. 87, 462-472.

Dailey86: Dailey HA (1986). "Purification and characterization of bacterial ferrochelatase." Methods Enzymol 123;408-15. PMID: 3702737

Jordan86: Jordan PM, Laghai-Newton A (1986). "Purification of 5-aminolevulinate synthase." Methods Enzymol 123;435-43. PMID: 3702741

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Tue Nov 25, 2014, BIOCYC14B.