Heme biosynthesis (WP102)

Saccharomyces cerevisiae

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. Based on Glycolysis and Gluconeogenesis Pathways at SGD and on Kruckeberg, AL and Dickinson, JR (2004) Carbon Metabolism in The Metabolism and Molecular Physiology of Saccharomyces cerevisiae, Dickinson, JR and Schweizer, M, eds, CRC Press. Description source: Wikipedia http://en.wikipedia.org/wiki/Heme


Kdahlquist , Thomas Kelder , Caroline Miller , Christine Chichester , Egon Willighagen , Martina Summer-Kutmon , Eric Weitz , and Kristina Hanspers


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Saccharomyces cerevisiae



Pathway Ontology

heme biosynthetic pathway


Label Type Compact URI Comment
coproporphyrinogen III Metabolite cas:2624-63-7
protoheme Metabolite cas:14875-96-8
Protoporphyrinogen IX Metabolite chebi:15435
protoporphyrin IX Metabolite cas:553-12-8
H+ Metabolite chebi:15378
porphobilinogen Metabolite cas:487-90-1
succinyl-CoA Metabolite chebi:15380
Porphobilinogen Metabolite chebi:17381
O2 Metabolite chebi:29371
glycine Metabolite chebi:57305
uroporphyrinogen III Metabolite cas:1976-85-8
Water Metabolite hmdb:HMDB02111
CoA Metabolite chebi:15346
hydroxymethylbilane Metabolite cas:73023-76-4
NH3 Metabolite chebi:16134
Iron(2+) Metabolite chebi:29033
H2O2 Metabolite chebi:16240
O2 Metabolite chebi:29371
Water Metabolite hmdb:HMDB02111
Water Metabolite hmdb:HMDB02111
CO2 Metabolite chebi:16526
CO2 Metabolite chebi:16526
CO2 Metabolite chebi:16526
HEM13 GeneProduct ensembl:YDR044W
HEM12 GeneProduct ensembl:YDR047W
HEM1 GeneProduct ensembl:YDR232W
HEM4 GeneProduct ensembl:YOR278W
HEM2 GeneProduct ensembl:YGL040C
HEM3 GeneProduct ensembl:YDL205C
HEM14 GeneProduct ensembl:YER014W
HEM15 GeneProduct ensembl:YOR176W


  1. Metabolism and Molecular Physiology of Saccharomyces Cerevisiae [Internet]. Dickinson JR, editor. Taylor & Francis; 1998. Available from: http://dx.doi.org/10.1201/9781482295405 DOI Scholia