Cloning, Sequence Analysis, and Expression in Escherichia coli of the Gene Encoding the Candida utilis Urate Oxidase (Uricase)

Abstract

A urate oxidase (uricase) gene was cloned from Candida utilis with an oligonucleotide probe based on the amino acid sequence of cyanogen bromide-cleaved uricase. The uricase gene contains 909 base pairs and encodes a protein with a predicted mass of 34, 193 Da. Candida uricase was similar (49% match in amino acid sequence) to the uricase from Aspergillus flavus. The uricase from Candida utilis has four cysteines and one of them, Cys168, participates in the enzyme activity. This enzyme was expressed to a level of about 20% of total cellular protein in an Escherichia coli cell as a soluble and functional form.