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Urease decomposes urea to ammonia, and has application potential in agriculture and medical treatment. Urease proteins include structural proteins (UreA, UreB and UreC) and accessory proteins (UreD/UreH, UreE, UreF and UreG), each of them has its own unique role in urease maturation. The structural proteins form the active center of urease, and the accessory proteins are responsible for the delivery of nickel. We review here the structure and function of bacterial urease complexes, and how each protein interacts to complete the activation process. We hope to provide theoretical basis for the regulation of urease activity and the development of urease inhibitors.

Using lipase segregation agar containing trioleoylglycerol, we obtained 18 lipase positive clones by screening from a metagenome library of dairy rumen microflora containing 15,360 clones. The average insert size of lipase positive clones was about 60 kb. Lipase enzyme activity analysis by p-NPP method indicated that Lipase6, Lipase7 and Lipase8 had higher lipolytic activities to substrates of p-nitrophenyl palmitate (C16), p-nitrophenyl alaurate (C12) and p-nitrophenyl palmitate (C16) respectively. The optimum pH of Lipase 6, Lipase 7 and Lipase 8 were 7.5. The halflife period of Lipase 8 with the value of 15 min in 70 degrees C decreased with the increase of temperature. In conclusion, the lipases screened in this study had different substrates specificity and good thermo stability, which laid a basis for large-scale industrial application.