Uroporphyrinogen III synthase

crystal structure of uroporphyrinogen iii synthase from an extremely thermophilic bacterium thermus thermophilus hb8 (wild type, native, form-2 crystal)

Identifiers

Symbol

HEM4

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe; PDBj
PDBsum	structure summary

Uroporphyrinogen III synthase EC 4.2.1.75 is an enzyme involved in the metabolism of the cyclic tetrapyrrole compound porphyrin. It is involved in the conversion of hydroxymethyl bilane into uroporphyrinogen III. This enzyme catalyses the inversion of the final pyrrole unit (ring D) of the linear tetrapyrrole molecule, linking it to the first pyrrole unit (ring A), thereby generating a large macrocyclic structure, uroporphyrinogen III.^[1] The enzyme folds into two alpha/beta domains connected by a beta-ladder, the active site being located between the two domains.^[2]

Pathology

A deficiency is associated with Gunther's disease, also known as congenital erythropoietic porphyria (CEP). This is an autosomal recessive inborn error of metabolism that results from the markedly deficient activity of uroporphyrinogen III synthase .^[3]

External links

Uroporphyrinogen III synthase at the US National Library of Medicine Medical Subject Headings (MeSH)

References

↑ Raux E, Schubert HL, Warren MJ (December 2000). "Biosynthesis of cobalamin (vitamin B12): a bacterial conundrum". Cell. Mol. Life Sci. 57 (13-14): 1880–93. doi:10.1007/PL00000670. PMID 11215515.
↑ Mathews MA, Schubert HL, Whitby FG, Alexander KJ, Schadick K, Bergonia HA, Phillips JD, Hill CP (November 2001). "Crystal structure of human uroporphyrinogen III synthase". EMBO J. 20 (21): 5832–9. doi:10.1093/emboj/20.21.5832. PMC 125291. PMID 11689424.
↑ To-Figueras J, Badenas C, Mascaro JM, Madrigal I, Merino A, Bastida P, Lecha M, Herrero C (2007). "Study of the genotype-phenotype relationship in four cases of congenital erythropoietic porphyria". Blood Cells Mol. Dis. 38 (3): 242–6. doi:10.1016/j.bcmd.2006.12.001. PMID 17270473.

This article incorporates text from the public domain Pfam and InterPro IPR003754

Enzymes involved in the metabolism of heme and porphyrin

Porphyrin biosynthesis

early mitochondrial:	Aminolevulinic acid synthase ALAS1 ALAS2

cytosolic:	Porphobilinogen synthase Porphobilinogen deaminase Uroporphyrinogen III synthase Uroporphyrinogen III decarboxylase

late mitochondrial:	Coproporphyrinogen III oxidase Protoporphyrinogen oxidase Ferrochelatase

Heme degradation
to bile

spleen:	Heme oxygenase Biliverdin reductase

liver:	glucuronosyltransferase UGT1A1

Carbon-oxygen lyases (EC 4.2) (primarily dehydratases)

4.2.1: Hydro-Lyases	Carbonic anhydrase Fumarase Aconitase Enolase Alpha Enolase 2 Enoyl-CoA hydratase/3-Hydroxyacyl ACP dehydrase Methylglutaconyl-CoA hydratase Tryptophan synthase Cystathionine beta synthase Porphobilinogen synthase 3-Isopropylmalate dehydratase Urocanase Uroporphyrinogen III synthase Nitrile hydratase

4.2.2: Acting on polysaccharides	Hyaluronate lyase

4.2.3: Acting on phosphates	Threonine synthase

4.2.99: Other	Carboxymethyloxysuccinate lyase

Enzymes

Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Enzyme kinetics Lineweaver–Burk plot Michaelis–Menten kinetics

Regulation	Allosteric regulation Cooperativity Enzyme inhibitor

Classification	EC number Enzyme superfamily Enzyme family List of enzymes

Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list)

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