PMID: 16545381

Authors:

Gabison L, Chiadmi M, Colloc'h N, Castro B, El Hajji M, Prange T

Title:

Recapture of [S]-allantoin, the product of the two-step degradation of uric acid, by urate oxidase.

Journal:

FEBS Lett. 2006 Apr 3;580(8):2087-91. Epub 2006 Mar 10.

Abstract:

Urate oxidase from Aspergillus flavus catalyzes the degradation of uric acid to [S]-allantoin through 5-hydroxyisourate as a metastable intermediate. The second degradation step is thought either catalyzed by another specific enzyme, or spontaneous. The structure of the enzyme was known at high resolution by X-ray diffraction of I222 crystals complexed with a purine-type inhibitor (8-azaxanthin). Analyzing the X-ray structure of urate oxidase treated with an excess of urate, the natural substrate, shows unexpectedly that the active site recaptures [S]-allantoin from the racemic end product of a second degradation step.