Center for Bioinformatics
Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases

Basic Information

Enzyme Number

Official Name

hydroxymethylbilane synthase

Name from literature

uroporphyrinogen synthase

Pathway from literature

porphyrin synthesis

Pathway from KEGG

Metabolism of Cofactors and Vitamins; Porphyrin and chlorophyll metabolism; map00860


Rat (10116)

Genome localization

8q22[25709 ],


The enzyme works by stepwise addition of pyrrolylmethyl groups until a hexapyrrole is present at the active centre. The terminal tetrapyrrole is then hydrolysed to yield the product, leaving a cysteine-bound dipyrrole on which assembly continues. In the presence of a second enzyme, EC uroporphyrinogen-III synthase, which is often called cosynthase, the product is cyclized to form uroporphyrinogen-III. If EC is absent, the hydroxymethylbilane cyclizes spontaneously to form uroporphyrinogen I.

Rate-limiting Description

"The results show that the rate-limiting enzyme for the hepatic conversion of 5-aminolaevulinate into protoporphyrin is porphobilinogen deaminase." (7326026)

Gene ontology

Gene ontology

GO:0004418 (F) hydroxymethylbilane synthase activity [P19356 ];
GO:0006783 (P) heme biosynthetic process [P19356 ];




Entrez Gene


  Copyright 2009, Center for Bioinformatics 
  Last Modified: 2009-03-24  
  Design by Zhao Min