IUBMB Enzyme Nomenclature


Accepted name: uroporphyrinogen-III synthase

Reaction: hydroxymethylbilane = uroporphyrinogen III + H2O

For diagram of reaction click here (mechanism).

Other name(s): porphobilinogenase; uroporphyrinogen isomerase; uroporphyrinogen III cosynthase; URO-synthase; hydroxymethylbilane hydro-lyase (cyclizing)

Systematic name: hydroxymethylbilane hydro-lyase (cyclizing; uroporphyrinogen-III-forming)

Comments: In the presence of EC, hydroxymethylbilane synthase, enzyme forms uroporphyrinogen III from porphobilinogen.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 37340-55-9


1. Battersby, A.R., Fookes, C.J.R., Matcham, G.W.J. and McDonald, E. Biosynthesis of the pigments of life: formation of the macrocycle. Nature 285 (1980) 17-21. [PMID: 6769048]

2. Tsai, S.-F., Bishop, D.F. and Desnick, R.J. Purification and properties of uroporphyrinogen III synthase from human erythrocytes. J. Biol. Chem. 262 (1987) 1268-1273. [PMID: 3805019]

[EC created 1982]

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