Expression and enzymatic properties of urate oxidase from Candida utilis in Lactococcus lactis
10.13200/j.cnki.cjb.004474
- VernacularTitle:产朊假丝酵母尿酸氧化酶在乳酸乳球菌中的表达及其酶学性质
- Author:
SHI Ping,LIU
- Publication Type:Journal Article
- Keywords:
Urate oxidase(UOX);
Recombinant expression;
Lactic acid bacteria;
Enzymatic properties;
Candida utilis
- From:
Chinese Journal of Biologicals
2025;38(05):543-548+556
- CountryChina
- Language:Chinese
-
Abstract:
Objective To express urate oxidase(UOX) from Candida utilis in lactic acid bacteria and study its enzymaticproperties, so as to provide technical supports for the application and development of UOX.MethodsThe optimized UOXgene was synthesized and cloned into the vector pTRKH2 to construct the recombinant expression plasmid, which was thenelectroporated to competent Lactococcus lactis NZ9000 to screen the recombinant strain and express the recombinant UOX(rUOX) with His-tag. Using UOX enzyme activity as an index, the fermentation conditions of recombinant bacteria were opti-mized. The rUOX was purified by nickel ion metal chelate chromatography, and its enzymatic properties were characterized.ResultsThe optimum expression conditions of the recombinant strain were as follows: fermentation temperature 37 ℃,fermentation time 12 h, and initial pH 6 of fermentation medium, respectively, and the rUOX enzyme activity reached(44. 57 ±0. 43) U/mL. The relative molecular mass of purified rUOX was about 35 000, consistent with the theoretical relative molecu-lar mass, and the specific activity was 17. 48 U/mg. The optimum pH and temperature of rUOX were 11. 5 and 45 ℃, andunder the optimal conditions, the K_m, V_(max)and k_(cat)values of rUOX were 5. 72 mmol/L, 71. 25 μmol/(L·min) and 95. 76/s,respectively, with uric acid as the substrate. Various metal ions and chemical reagents had inhibitory activity on rUOX, whileTween 20 exhibited obvious activation activity on rUOX.ConclusionThe recombinant expression of UOX in lactic acidbacteria is feasible, and its enzyme activity is relatively stable, which provides an experimental basis for the development andapplication of UOX under alkali-tolerant conditions.
