本文選題：凝結(jié)芽孢桿菌 + N-乙酰-β-D-氨基葡萄糖苷酶��； 參考：《林業(yè)工程學(xué)報(bào)》2017年02期

【摘要】：N-乙酰-β-D-氨基葡萄糖苷酶(N-acetyl-β-D-glucosaminidase,NAGase)是微生物幾丁質(zhì)酶系中不可缺少的一部分,近年來由于其在幾丁質(zhì)降解過程中的特殊作用而受到關(guān)注。筆者從凝結(jié)芽孢桿菌NL01基因組上克隆獲得了1個(gè)假定的N-乙酰-β-D-氨基葡萄糖苷酶基因,長(zhǎng)度為1 761 bp,編碼586個(gè)氨基酸,蛋白質(zhì)理論分子量為64.5 k Da,編碼氨基酸序列與已報(bào)道的N-乙酰-β-D-氨基葡萄糖苷酶相似性僅為38%。將該基因克隆至表達(dá)載體pETDuet-1上,并在大腸桿菌BL21(DE3)中進(jìn)行重組表達(dá),結(jié)果顯示重粗酶具有N-乙酰-β-D-氨基葡萄糖苷酶活力,經(jīng)鎳柱純化獲得純酶的比酶活為74.3 U/mg。對(duì)重組酶酶學(xué)性質(zhì)研究發(fā)現(xiàn),該酶是一種新型耐高溫N-乙酰-β-D-氨基葡萄糖苷酶。最適pH為5.5,最適溫度為75℃,pH和熱穩(wěn)定性較好,在pH 3.5~7.5范圍內(nèi)比較穩(wěn)定,在不高于65℃條件下熱處理30 min后,酶活力可以保持在70%以上。
[Abstract]:N-acetyl- 尾 -D-glucosaminidase (NAGase) is an indispensable part of microbial chitinase system. Recently, N-acetyl- 尾 -D-glucosaminidase (N-acetyl- 尾 -D-glucosaminidase) has attracted much attention in recent years because of its special role in chitin degradation. A hypothetical N- acetyl- 尾 -D- glucosaminidase gene was cloned from the genome of Bacillus coagulans NL01, with a length of 1 761 BP encoding 586 amino acids. The theoretical molecular weight of the protein is 64.5 kDa, and the similarity between the encoded amino acid sequence and the reported N-acetyl- 尾 -D- glucosaminidase is only 38. The gene was cloned into the expression vector pETDuet-1 and expressed in E. coli BL21 (DE3). The results showed that the heavy crude enzyme had the activity of N-acetyl- 尾 -D- glucosaminidase, and the specific activity of the purified enzyme was 74.3% Umg. The enzymatic properties of the recombinant enzyme were studied. It was found that the recombinant enzyme was a new type of high temperature resistant N acetyl-尾-D-glucosaminidase. The optimum pH was 5.5, the optimum temperature was 75 鈩，

本文編號(hào)：2057503