Heme Biosynthesis (Danio rerio)

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Black - reactantsrate limiting stepRed - side productsFe2+H+delta-aminolevulinateprotoporphyrinogen IXdelta-aminolevulinateprotohemealas2PorphobilinogenfechglycineH2OH2OCO2porphobilinogenCO2zgc:110219CoAO2HMBSprotoporphyrin IXcpoxuroporphyrinogen IIIsuccinyl-CoAalas1O2H2OhydroxymethylbilaneurodNH3uroscoproporphyrinogen IIIppoxH2O2CO2


Description

The enzymatic process that produces heme is properly called porphyrin synthesis, as all the intermediates are tetrapyrroles that are chemically classified are porphyrins. The process is highly conserved across biology. In humans, this pathway serves almost exclusively to form heme. In other species, it also produces similar substances such as cobalamin (vitamin B12).

The pathway is initiated by the synthesis of D-Aminolevulinic acid (dALA or ╬┤ALA) from the amino acid glycine and succinyl-CoA from the citric acid cycle (Krebs cycle). The rate-limiting enzyme responsible for this reaction, ALA synthase, is strictly regulated by intracellular iron levels and heme concentration. A low-iron level, e.g., in iron deficiency, leads to decreased porphyrin synthesis, which prevents accumulation of the toxic intermediates. This mechanism is of therapeutic importance: infusion of heme arginate or hematin can abort attacks of porphyria in patients with an inborn error of metabolism of this process, by reducing transcription of ALA synthase.

The organs mainly involved in heme synthesis are the liver and the bone marrow, although every cell requires heme to function properly. Heme is seen as an intermediate molecule in catabolism of haemoglobin in the process of bilirubin metabolism.

Source: Wikipedia http://en.wikipedia.org/wiki/Heme

Comments

HomologyConvert 
This pathway was inferred from Homo sapiens pathway WP561(r21860) with a 53% conversion rate.

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Ontology Terms

 

Bibliography

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History

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CompareRevisionActionTimeUserComment
89921view13:34, 6 October 2016MkutmonModified description
88638view14:51, 12 August 2016JmeliusOntology Term : 'heme biosynthetic pathway' added !
71976view00:26, 24 October 2013MaintBotremoved data source from nodes without identifier
71939view21:40, 23 October 2013EgonwConverted labels into Metabolite DataNodes.
71938view21:37, 23 October 2013EgonwSplit two metabolites in one Label into two grouped Metabolite DataNodes.
70148view21:34, 12 July 2013MaintBotupdated to 2013 schema
40777view22:15, 1 March 2011MaintBotRemoved redundant pathway information and comments
35295view22:56, 11 February 2010Mills42Modified description
34169view21:17, 9 December 2009MaintBotAutomatic update of empty xrefs
31911view12:50, 14 August 2009MaintBotFixed group labels
31024view01:11, 30 July 2009MaintBotNew pathway

External references

DataNodes

View all...
NameTypeDatabase referenceComment
CO2MetaboliteHMDB01967 (HMDB)
CoAMetaboliteHMDB01423 (HMDB)
Fe2+Metabolite
H+Metabolite
H2O2MetaboliteHMDB03125 (HMDB)
H2OMetaboliteHMDB02111 (HMDB)
HMBSGeneProduct
NH3MetaboliteHMDB00051 (HMDB)
O2MetaboliteHMDB01377 (HMDB)
PorphobilinogenMetaboliteHMDB00245 (HMDB)
alas1GeneProduct64608 (Entrez Gene)
alas2GeneProduct64607 (Entrez Gene)
coproporphyrinogen IIIMetabolite
cpoxGeneProduct321294 (Entrez Gene)
delta-aminolevulinateMetabolite
fechGeneProduct58215 (Entrez Gene)
glycineMetabolite
hydroxymethylbilaneMetabolite
porphobilinogenMetabolite
ppoxGeneProduct664750 (Entrez Gene)
protohemeMetabolite
protoporphyrin IXMetabolite
succinyl-CoAMetabolite
urodGeneProduct30617 (Entrez Gene)
uroporphyrinogen IIIMetabolite
urosGeneProduct404731 (Entrez Gene)
zgc:110219GeneProduct550338 (Entrez Gene)

Annotated Interactions

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