Heme biosynthesis (WP269)

Drosophila melanogaster

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 δALA) 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


Kdahlquist , Caroline Miller , Christine Chichester , Egon Willighagen , Martina Summer-Kutmon , and Eric Weitz


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Drosophila melanogaster



Pathway Ontology

heme biosynthetic pathway


Label Type Compact URI Comment
O2 Metabolite chebi:15379
O2 Metabolite chebi:15379
Fe2+ Metabolite chebi:29033
delta-aminolevulinate Metabolite chebi:17549
CoA Metabolite chebi:15346
succinyl-CoA Metabolite chebi:15380
CO2 Metabolite chebi:16526
2 H2O Metabolite chebi:15377
H2O Metabolite chebi:15377
4 CO2 Metabolite chebi:16526
2 CO2 Metabolite chebi:16526
glycine Metabolite chebi:15428
Updo GeneProduct ncbigene:35986
Coprox GeneProduct ncbigene:44701
ferrochelatase GeneProduct ncbigene:43757
Ppox GeneProduct ncbigene:42939
Alas GeneProduct ncbigene:37815
CG1885 GeneProduct ncbigene:31817
l(3)02640 GeneProduct ncbigene:46140
Pbgs GeneProduct ncbigene:39402