Triphosgene was used to react with γ-chloroethyl glutamate, which was synthesized from 2-ethylene chlorohydrin and L-glutamic acid, to give γ-chloroethyl glutamate N-carboxyan.hydride (NCA). Thus, poly(γ-chloroethy...Triphosgene was used to react with γ-chloroethyl glutamate, which was synthesized from 2-ethylene chlorohydrin and L-glutamic acid, to give γ-chloroethyl glutamate N-carboxyan.hydride (NCA). Thus, poly(γ-chloroethyl glutamate), a new poly (amino acid) with reactive chloride, was obtained from the NCA by using triethylamine as the initiator which can lead to intrinsic viscosity of polypeptide, [η], over 50 mL/g. NCA and polymer were characterized by IR, 1H NMR and 13C NMR. Oligomer of γ-chloroethyl glutamate was also obtained while NCA was initiated by moisture in air. The conforma- tions of oligomer and polymer of γ-chloroethyl glutamate were observed by IR and CD spectroscopy. The results suggested that the conformation of oligomer mainly be β-sheet, while the polymer be α-helix.展开更多
在谷氨酸棒状杆菌( Corynebacterium glutamicum )SNK118中表达NADP +依赖型的3-磷酸甘油醛脱氢酶编码基因,提高胞内NADPH水平,以提高 L -精氨酸( L -Arginine)和 L -鸟氨酸(L-Ornithine)发酵产量。通过NCBI数据库检索,选取了3个不同来...在谷氨酸棒状杆菌( Corynebacterium glutamicum )SNK118中表达NADP +依赖型的3-磷酸甘油醛脱氢酶编码基因,提高胞内NADPH水平,以提高 L -精氨酸( L -Arginine)和 L -鸟氨酸(L-Ornithine)发酵产量。通过NCBI数据库检索,选取了3个不同来源的3-磷酸甘油醛脱氢酶编码基因。经测定酶活力,最终选择糖丁基梭菌( Clostridium saccharobutylicum) DSM13864来源的NADP +依赖型的3-磷酸甘油醛脱氢酶基因( CsgapC )。构建了产 L -精氨酸的重组菌SNK118/pXMJ19- CsgapC,当摇瓶发酵70 h时产 L -精氨酸11.55 g/L,糖酸转化率0.13 g/g,与对照菌SNK118/pXMJ19相比,精氨酸产量和糖酸转化率分别提高了26%和10.2%。在 L -鸟氨酸生产菌株SNK118Δ argF Δ argR 中重组表达 CsgapC,重组菌SNK118Δ argF Δ argR /pXMJ19- CsgapC 摇瓶发酵70 h产 L -鸟氨酸27.76 g/L,糖酸转化率0.274 g/g,与对照菌SNK118Δ argF Δ argR /pXMJ19相比, L -鸟氨酸产量和糖酸转化率分别提高了20.1%和15.6%。结果表明,异源表达 CsgapC 有助于提高谷氨酸棒杆菌发酵生产 L -精氨酸和 L -鸟氨酸的水平。展开更多
文摘Triphosgene was used to react with γ-chloroethyl glutamate, which was synthesized from 2-ethylene chlorohydrin and L-glutamic acid, to give γ-chloroethyl glutamate N-carboxyan.hydride (NCA). Thus, poly(γ-chloroethyl glutamate), a new poly (amino acid) with reactive chloride, was obtained from the NCA by using triethylamine as the initiator which can lead to intrinsic viscosity of polypeptide, [η], over 50 mL/g. NCA and polymer were characterized by IR, 1H NMR and 13C NMR. Oligomer of γ-chloroethyl glutamate was also obtained while NCA was initiated by moisture in air. The conforma- tions of oligomer and polymer of γ-chloroethyl glutamate were observed by IR and CD spectroscopy. The results suggested that the conformation of oligomer mainly be β-sheet, while the polymer be α-helix.
