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porphobilinogen deaminase; PBG-D; hydroxymethylbilane synthase; HMBS; pre-uroporphyrinogen synthase (HMBS, PBGD, UPS)
Function:
- tetrapolymerization of the monopyrrole porphobilinogen (PBG) into the hydroxymethylbilane pre-uroporphyrinogen in several discrete steps
4 porphobilinogen + H2O = hydroxymethylbilane + 4 NH3
- porphyrin metabolism; protoporphyrin-IX biosynthesis
- coproporphyrinogen-III from 5-aminolevulinate: step 2/4
Cofactor:
- binds 1 dipyrromethane group covalently
- the porphobilinogen subunits are added to the dipyrromethane group
Structure: belongs to the HMBS family
Compartment: cytoplasm (probable)
Alternative splicing: named isoforms=2
Expression:
- isoform 1 is ubiquitously expressed
- isoform 2 is found only in erythroid cells
Pathology:
- defects in HMBS are the cause of acute intermittent porphyria
Interactions
molecular events
Related
heme synthesis
General
ammonia lyase
phosphoprotein
Properties
SIZE: entity length = 361 aa
MW = 39 kD
COMPARTMENT: cytoplasm
MOTIF: Ser phosphorylation site {S15}
Database Correlations
OMIM correlations
MORBIDMAP 609806
UniProt P08397
PFAM correlations
Entrez Gene 3145
Kegg hsa:3145
ENZYME 2.5.1.61
References
- UniProt :accession P08397
- GeneReviews
http://www.ncbi.nlm.nih.gov/sites/genetests/lab/gene/HMBS