Recombinant Expression and Functional Assessment of Uricase from a Pertinent Origin of the Enzyme, Streptomyces sp. Strain 17-1.

Uricase or urate oxidase, as a therapeutic enzyme, is extensively applied to oxidize accumulated uric acid in the body to soluble form to treat related illnesses. This study was conducted with the aim of searching for potential sources of uricase-producing Streptomyces from Eshtehard salt desert in Alborz province, Iran and heterologous expression, purification and functional assay of the enzyme. Main screening was conducted by cultivation of the strains on a medium enriched with 0.3 percent (w/v) uric acid. The uricase gene from the most potent strain was then recombinantly expressed in E. coli BL21 (DL3). Out of the tested strains, only seven showed uricase activity. The highest level of native uricase activity (11.5735 U.mL-1) belonged to strain 17-1, which had the closest similarity to Streptomyces nigra. A recombinant uricase with a molecular mass of approximately 38 kDa was produced. The purified uricase exhibited a specific activity of about 28.29±0.59 U.mg-1, which is among the highest level of uricase activity reported by other studies. This enzyme is a promising candidate for further applicable investigations and large-scale production in terms of its large volume of soluble expression and selective competitive activity.