Purification and properties of a novel acid urease applied to Chinese rice wine
It has been demonstrated acid urease is capable of decomposing urea in fermented beverage and foods, meanwhile serves as a precursor of ethylcarbamate, a potential carcinogenic compound. We here report the purification and characterization of a novel acid urease applied for the removal of urea in Chinese rice wine from Enterobactria sp.R-SYB082.The enzyme was purified to electrophoretic homogeneity using three successive steps including ethanol precipitation, superdex 200 and Mono Q with a yield and purification-fold of 42％ and 21.1 respectively. The molecular weight of the enzyme was estimated to be 430,000 by gel filtration and 72,000 by SDS-PAGE, suggesting that its a hexamer comprising of six identical subunits. The purified enzyme was optimally active at 35 ℃ And at pH4.5.The activity was stable between a pH range of 4.0 and 6.0. It was stable when up to 55 ℃, but stability of acid urease decrease rapidly above 65 ℃. The apparent Km and Vmax value for hydrolyzing of urea were 19.5 μmol/L and 0.87 μmol/min respectively. Over 85％ of urea in two kinds of Chinese rice wine was decomposed by incubating with the enzyme (0.08 U/ml) at 35 ℃ For 7 days, in comparison to above 78％ of urea removal at 20 ℃. The result showed that the enzyme is applicable to eliminate of urea in Chinese rice wine.
Enterobactria sp. acid urease ethylcarbamate urea Chinese rice wine
Luqiang Yang Songhua Wang Yaping TIAN
The Key Laboratory of Industrial Biotechnology,Ministry of Education,Jiangnan University,Wuxi,214122,China
国际会议
The 5th International Conference on Separation Science and Technology(第五届国际分离科学与技术会议)
北京
英文
2007-10-14（万方平台首次上网日期，不代表论文的发表时间）