Modification of a reactive cysteine explains differences between rasburicase and Uricozyme®, a natural Aspergillus flavus uricase

Abstract

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.

Elitek™–rasburicase: an effective means to prevent and treat hyperuricemia associated with tumor lysis syndrome, a Meeting Report, Dallas, Texas, January 2002

“…Nonrecombinant urate oxidase contains a cysteine adduct resulting from its process of purification that lowers its activity. 46 In contrast, the molecular structure of rasburicase is preserved by its process of production. 46 Dr Pui further reviewed frequency of acute renal failure in patients with advanced B-cell malignancies such as stage III/IV lymphoma and B-cell ALL.…”

“…46 In contrast, the molecular structure of rasburicase is preserved by its process of production. 46 Dr Pui further reviewed frequency of acute renal failure in patients with advanced B-cell malignancies such as stage III/IV lymphoma and B-cell ALL. Allopurinol was administered to 230 patients in three studies conducted by the Pediatric Oncology Group (POG), 47 UK Children's Cancer Study Group, 48 and St Jude's.…”

“…Purification of urate oxidase involved extraction procedures that cause some oxidative degradation of the enzyme. 46 Since this process was developed over 25 years ago, the drug was stabilized with agents that have never been fully characterized.…”

Reduced-dose rasburicase (recombinant xanthine oxidase) in adult cancer patients with hyperuricemia

“…Expression of the gene encoding urate oxidase in yeast yields recombinant enzyme in therapeutically useful quantities. 5 Recombinant urate oxidase (rasburicase) has been found to be useful prophylactically and therapeutically for hyperuricemia in children 6 and adults. 7 Rasburicase administration at the recommended dose of 0.2 mg/kg for 3-7 days results in dramatically reduced levels of serum uric acid, usually substantially lower than the lower limit of normal.…”

PLP-Dependent Enzymes: a Potent Therapeutic Approach for Cancer and Cardiovascular Diseases

“…Currently, PEGylation become a well developed technique for formulations of biopharmaceuticals for improving their solubility, bioavailability and decreasing their immunogenic properties as approved by FDA organization (Pasut et al, 2007). PEGylated forms of therapeutic enzymes as Escherichia coli asparaginase (Abuchowski et al, 1979), arginine deiminase (Izzo et al, 2007), Bacillus subtilis arginase (Cheng et al, 2005), Aspergillus flavus uricase (Bayol et al, 2002) displays affordable therapeutic potentialities comparing to corresponding free enzymes, as declared by FDA. PEGylation of Pseudomonas putida L-methioninase was extensively studied (Tan et al, 1998 andSun et al, 2003).…”