uroporphyrinogen-III synthase; UROIIIS; UROS; hydroxymethylbilane hydrolyase [cyclizing]; uroporphyrinogen-III cosynthase (UROS)

Function

• catalyzes cyclization of the linear tetrapyrrole, hydroxymethylbilane, to the macrocyclic uroporphyrinogen III, the branch point for various sub-pathways leading to a diversity of porphyrins
• porphyrins act as cofactors for many enzymes including methionine synthesis (vitamin B12) or oxygen transport (heme)
• porphyrin metabolism; protoporphyrin-IX biosynthesis
• coproporphyrinogen-III from 5-aminolevulinate: step 3/4

hydroxymethylbilane = uroporphyrinogen III + H2O

Structure

• monomer
• belongs to the uroporphyrinogen-III synthase family

Expression

ubiquitous

Pathology

• defects in UROS are the cause of congenital erythropoietic porphyria

More general terms

• hydro-lyase, hydratase or dehydratase

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=7390
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:7390
• OMIM: https://mirror.omim.org/entry/263700
• OMIM: https://mirror.omim.org/entry/606938
• UniProt: http://www.uniprot.org/uniprot/P10746.html