Recombinant urate-oxidase (rUOX) produced in E.Coli is a tetrameric protein with identical subunits of a molecular mass of about 34 kDa. The cDNA coding for urate-oxidase was cloned from a strain of Aspergillus flavus . The monomer, made up of a single 302 amino acid polypeptide chain, has no intra- or inter-disulfide bridges. The drug product is a sterile, white to off-white, lyophilized powder intended for intravenous administration following reconstitution and is supplied in 3-mL colorless, glass vials containing 1.5 mg recombinant urate-oxidae, 5.0 mg sucrose, 25.0 mg L-glycine, 1.0mg Tween-80 and between 12.6 and 14.3 mg of dibasic sodium phosphate.