A novel method for enzymatic synthesis of L-theanine using copper(Ⅱ)-L-glutamine[Cu(Gln)2]as donor substrate was proposed.The structure of Cu(Gln)2 was identified by infrared spectrum analysis and its stability was a...A novel method for enzymatic synthesis of L-theanine using copper(Ⅱ)-L-glutamine[Cu(Gln)2]as donor substrate was proposed.The structure of Cu(Gln)2 was identified by infrared spectrum analysis and its stability was also investigated under the reaction conditions.The enzymatic synthesis of L-theanine catalyzed by γ-glutamyltranspeptidase was carried out by using Cu(Gln)2 and L-glutamine as donor substrate respectively,and the product yield and conversion rate of donor substrate were compared under the conditions of different ratios of donor and acceptor.The results showed that the transpeptidation reaction could be effectively enhanced by using Cu(Gln)2 as donor substrate.The conversion rate of donor would increase by 51.5%,44.9% and 27.1% under different reaction conditions,compared to that using L-Gln as donor substrate.When the molar ratio of donor to acceptor was 6∶100,a higher donor conversion of 71.3% was obtained.展开更多
Two compound crystals of (Hdafo)2·2H2O (1) and (Hdafo)2·2H2O (2) were obtained when we tried synthesizing the mixed ligand compounds of Zinc (Ⅱ)and Cobalt(Ⅱ)with 4,5 diazafluorene 9 one(dafo) and o phthali...Two compound crystals of (Hdafo)2·2H2O (1) and (Hdafo)2·2H2O (2) were obtained when we tried synthesizing the mixed ligand compounds of Zinc (Ⅱ)and Cobalt(Ⅱ)with 4,5 diazafluorene 9 one(dafo) and o phthalic acid, respectively. Their structure was determined by single crystal X ray diffraction. The crystals all belong to monoclinic system, C2/c space group with crystallographic data:(Hdafo)2·2H2O, a=1.6768(5)nm, b=1.2052(3)nm, c=1.3888(4)nm, β=116.793(3), V=2.5053(12)nm3, Z=4, F(000)=1232, Mr=609.57, Dc=1.616g·cm-3, μ(MoKα)=1.444mm-1, R1=0.0373, wR2=0.0765; (Hdafo)2·2H2O, a=1.6787(4)nm, b=1.2078(3)nm, c=1.3911(4)nm, β=116.665(3)°, V=2.5204(11)nm3, Z=4, F(000)=1220, Mr=603.13, Dc=1.589g·cm-3, μ(MoKα)=1.142mm-1, R1=0.0257, wR2=0.0654. The constitutes of the two compounds were proved by elemental, IR Spectra and thermal analyses. CCDC: 1, 198516; 2, 198517.展开更多
文摘A novel method for enzymatic synthesis of L-theanine using copper(Ⅱ)-L-glutamine[Cu(Gln)2]as donor substrate was proposed.The structure of Cu(Gln)2 was identified by infrared spectrum analysis and its stability was also investigated under the reaction conditions.The enzymatic synthesis of L-theanine catalyzed by γ-glutamyltranspeptidase was carried out by using Cu(Gln)2 and L-glutamine as donor substrate respectively,and the product yield and conversion rate of donor substrate were compared under the conditions of different ratios of donor and acceptor.The results showed that the transpeptidation reaction could be effectively enhanced by using Cu(Gln)2 as donor substrate.The conversion rate of donor would increase by 51.5%,44.9% and 27.1% under different reaction conditions,compared to that using L-Gln as donor substrate.When the molar ratio of donor to acceptor was 6∶100,a higher donor conversion of 71.3% was obtained.
文摘Two compound crystals of (Hdafo)2·2H2O (1) and (Hdafo)2·2H2O (2) were obtained when we tried synthesizing the mixed ligand compounds of Zinc (Ⅱ)and Cobalt(Ⅱ)with 4,5 diazafluorene 9 one(dafo) and o phthalic acid, respectively. Their structure was determined by single crystal X ray diffraction. The crystals all belong to monoclinic system, C2/c space group with crystallographic data:(Hdafo)2·2H2O, a=1.6768(5)nm, b=1.2052(3)nm, c=1.3888(4)nm, β=116.793(3), V=2.5053(12)nm3, Z=4, F(000)=1232, Mr=609.57, Dc=1.616g·cm-3, μ(MoKα)=1.444mm-1, R1=0.0373, wR2=0.0765; (Hdafo)2·2H2O, a=1.6787(4)nm, b=1.2078(3)nm, c=1.3911(4)nm, β=116.665(3)°, V=2.5204(11)nm3, Z=4, F(000)=1220, Mr=603.13, Dc=1.589g·cm-3, μ(MoKα)=1.142mm-1, R1=0.0257, wR2=0.0654. The constitutes of the two compounds were proved by elemental, IR Spectra and thermal analyses. CCDC: 1, 198516; 2, 198517.
