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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1r51

E.C. namefactor-independent urate hydroxylase
SpeciesAspergillus flavus (Fungus)
E.C. Number (IntEnz) 1.7.3.3
CSA Homologues of 1r51There are 29 Homologs
CSA Entries With UniProtID Q00511
CSA Entries With EC Number 1.7.3.3
PDBe Entry 1r51
PDBSum Entry 1r51
MACiE Entry M0118

Literature Report

IntroductionUrate oxidase is an essential enzyme involved in purine degradation pathway. It is responsible for the conversion of uric acid to allantoin, thus catalysing the oxidative ring opening of the purine ring in the degradative pathway.
The enzyme is lacking in humans, it can therefore be used as a protein drug to treat / reduce toxic uric acid accumulation.
The active enzyme is a homotetramer, each dimer can be considered as a porin-like structure, with the 16 antiparallel strands superimposed in a reverse handed manner on those from a porin, the helices taking the place of the membrane.
The enzyme is a member of a family of proteins with multimeric barrels face to face related by two-fold symmetry, proposed to be a new family of tunnel-shaped proteins.
MechansimUrate oxidase catalyses the first step of the oxidation of uric acid. This reaction is followed by several uncatalysed steps to give allantoin. There is no prosthetic group or metal ion present in the catalytic reaction.
Unlike the oxidases, urate oxidase has no functionalgroups involved in the catalytic mechanism. The enzyme's catalytic activity results from isolating its substrates in the optimum geometry for the reaction to occur.
Uric acid is stabilised as a dianion by urate oxidase through hydrogen bonds with ARG 176 and GLN 228. GLN 228 is positioned to anchor the purine ring.
Reaction

Catalytic Sites for 1r51

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
Gln2280macie:sideChain
Arg1760macie:sideChain

Literature References

Notes:
Colloc'h N.
Crystal structure of the protein drug urate oxidase-inhibitor complex at 2.05 A resolution
Nat Struct Biol 1997 4 947-952
PubMed: 9360612
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