Purification, Properties, and Application of a Novel Acid Urease from Enterobacter sp

• Published in: Applied biochemistry and biotechnology Vol. 160; no. 2; pp. 303 - 313
• Main Authors: Yang, Lu-qiang, Wang, Song-hua, Tian, Ya-ping
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York New York : Humana Press Inc 2010; Humana Press Inc; Springer; Springer Nature B.V
• Subjects: Acids; Acids - chemistry; Bacteria; Bacterial Proteins - chemistry; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; Biochemistry; Biological and medical sciences; Biotechnology; Chemistry; Chemistry and Materials Science; Enterobacter; Enterobacter - chemistry; Enterobacter - enzymology; enzyme activity; Enzyme Stability; Enzymes; Ethanol; Fundamental and applied biological sciences. Psychology; Kinetics; Molecular Weight; optimization; Oryza sativa; polyacrylamide gel electrophoresis; purification; rice wines; Substrate Specificity; temperature; Temperature effects; urea; Urea - chemistry; urease; Urease - chemistry; Urease - isolation & purification; Urease - metabolism; Vitaceae; Urea; Ethylcarbamate; sp; Acid urease; Chinese rice wine; Wine; Monocotyledones; Purification; Enzyme; Urease; Oryza sativa; Enterobacter sp; Enterobacter; Gramineae; Angiospermae; Bacteria; Hydrolases; Spermatophyta; Application; Enterobacteriaceae; Rice
• ISSN: 0273-2289; 1559-0291
• DOI: 10.1007/s12010-008-8159-6

It has been demonstrated that acid urease is capable of decomposing urea in fermented beverage and foods. As urea is a precursor of ethylcarbamate, a potential carcinogenic compound, measures must be taken to control the level of urea. We herein describe the purification and characterization of a novel acid urease from Enterobacter sp. R-SYB082 and its application to the removal of urea in Chinese rice wine. The enzyme was purified to electrophoretic homogeneity using ethanol precipitation, Superdex 200 and Mono Q with a fold purification of 21.1 and a recovery of 49%. The molecular weight of the enzyme was 430,000 Da by gel filtration and 72,000 Da by sodium dodecyl sulfate polyacrylamide gel electrophoresis, suggesting that it was a hexamer. The activity of this purified enzyme was optimal at pH 4.5 and 35 °C. The temperature stability was under 55 °C, and the pH stability was 4.0~5.0. The enzyme exhibited an apparent K m of 19.5 μmol/l and a V max of 109 μmol urea/mg·min at 35 °C and pH 4.5. When incubating two different kinds of Chinese rice wine with the enzyme (0.08 U/ml) at 35 °C for 7 days, over 85% of urea was decomposed, and at 20 °C, above 78% was removed. The result showed that the enzyme is applicable to elimination of urea in Chinese rice wine.