發(fā)布時(shí)間：2018-06-19 03:29

  本文選題：三七皂苷 + 內(nèi)切纖維素酶　； 參考：《高等學(xué)�；瘜W(xué)學(xué)報(bào)》2017年12期

【摘要】：從嗜熱細(xì)菌基因組中克隆到1個(gè)新的纖維素酶基因,并在大腸桿菌中進(jìn)行了高效可溶性表達(dá),粗酶液經(jīng)鎳柱親和層析進(jìn)行分離純化.利用快速分離液相色譜-四極桿飛行時(shí)間質(zhì)譜聯(lián)用儀(RRLC/Q-TOF-MS)對(duì)重組內(nèi)切纖維素酶Fpendo5A轉(zhuǎn)化三七總皂苷的產(chǎn)物結(jié)構(gòu)進(jìn)行了鑒定,并進(jìn)一步闡明其轉(zhuǎn)化機(jī)制.結(jié)果表明,該酶的最適反應(yīng)溫度和pH值分別為80℃和5.5.Fpendo5A能夠催化三七總皂苷中的主要皂苷成分,即Ra_1,Rb_1,Rc,Rd和Rg_3的側(cè)鏈糖基的水解反應(yīng),但對(duì)于不同的皂苷底物,Fpendo5A選擇性催化的側(cè)鏈糖基類型不同.經(jīng)鑒定,Fpendo5A轉(zhuǎn)化Ra_1,Rb_1,Rc,Rd和Rg_3的轉(zhuǎn)化產(chǎn)物分別為Rb_2,GypⅩⅦ,CMC_1,F_2和Rh_2.由此可見,Fpendo5A通過(guò)水解Rb_1,Rc,Rd和Rg3的C3位的β-(1,2)糖苷鍵分別生成GypⅩⅦ,CMC1,F2和Rh2.在轉(zhuǎn)化Ra_1時(shí),Fpendo5A通過(guò)水解Ra_1的C20位的α-(1,4)木糖苷鍵生成Rb2.
[Abstract]:A new cellulase gene was cloned from the genome of thermophilic bacteria and expressed in Escherichia coli. The crude enzyme was purified by nickel affinity chromatography. The product structure of recombinant endocellulase Fpendo5A into panax notoginseng saponins was identified by rapid separation liquid chromatography-quadrupole time-of-flight mass spectrometry (RRLC / Q-TOF-MS), and the transformation mechanism was further elucidated. The results showed that the optimum reaction temperature and pH value of the enzyme were 80 鈩，

本文編號(hào)：2038205