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Modification of a reactive cysteine explains differences between rasburicase and Uricozyme®, a natural Aspergillus flavus uricase
Author(s) -
Bayol Alain,
Capdevielle Joël,
Malazzi Pascal,
Buzy Armelle,
Claude Bonnet Marie,
Colloc'h Nathalie,
Mor JeanPaul,
Loyaux Denis,
Ferrara Pascual
Publication year - 2002
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1042/ba20010083
Subject(s) - rasburicase , tetramer , urate oxidase , cysteine , chemistry , uric acid , adduct , enzyme , residue (chemistry) , biochemistry , aspergillus flavus , stereochemistry , organic chemistry , hyperuricemia , food science
Urate oxidase is used in humans for the control of uric acid in patients receiving chemotherapy. Rasburicase (Fasturtec®/Elitek®), a recombinant urate oxidase expressed in Saccharomyces cerevisiae , was compared with Uricozyme®, the natural enzyme produced by Aspergillus flavus. Rasburicase has a higher purity as demonstrated by SDS/PAGE and chromatographic analysis and a better specific activity. The differences observed for Uricozyme® are likely attributable to the previously used purification process, which modifies the enzyme. The production process of rasburicase, on the other hand, preserves the structure of the molecule. MS analysis shows that Uricozyme® contains a cysteine adduct on Cys 103 . In the crystal structure, the sulphur atom of the cysteine residue in position 103 is orientated to the external surface of the tetramer, whereas the sulphur atom of two other cysteine residues (Cys 35 and Cys 290 ) is orientated to the centre of the canal formed by the tetramer. The same adduct is produced by simple incubation of the rasburicase with cysteine.