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
The complex[Cu(L-met)(phen)(H 2 O)]NO 3 ·H 2 O has been synthesized and investigated by elemental analysis,molar conductivity,spec troscopic and X-ray diffraction methods,where phen =1,10-phenanthroline and L-met...The complex[Cu(L-met)(phen)(H 2 O)]NO 3 ·H 2 O has been synthesized and investigated by elemental analysis,molar conductivity,spec troscopic and X-ray diffraction methods,where phen =1,10-phenanthroline and L-met =L-methioninate group.The complex crystallized in the monoclinic space g roup P2 1 with a=12.053(2)*!,b=6.886(1)*!,c=13.385(3)*!,β=113.59(3)°,V=1018.1(3)*! 3 ,Z =2,D c =1.598g·cm -3 ,μ=1.223mm -1 ,F(000)=506,R 1 =0.0306,and w R 2 =0.0742.The copper*"atom is ligated in a distorted square-pyramidal geometry by two ni trogen atoms of one phen and the amino nitrogen atom ,one carboxylate oxygen atom of L-met in the base plane,and an aqua at t he apical position.A one-dimension al chain configuration formed by the hydrogen-bonding and weak Cu-O(the uncoordinated carboxyl oxygen a tom)coordination interactions be-tween neighboring[Cu(L-met)(phen)(H 2 O)] + cations.CCDC:183368.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The complex[Cu(L-met)(phen)(H 2 O)]NO 3 ·H 2 O has been synthesized and investigated by elemental analysis,molar conductivity,spec troscopic and X-ray diffraction methods,where phen =1,10-phenanthroline and L-met =L-methioninate group.The complex crystallized in the monoclinic space g roup P2 1 with a=12.053(2)*!,b=6.886(1)*!,c=13.385(3)*!,β=113.59(3)°,V=1018.1(3)*! 3 ,Z =2,D c =1.598g·cm -3 ,μ=1.223mm -1 ,F(000)=506,R 1 =0.0306,and w R 2 =0.0742.The copper*"atom is ligated in a distorted square-pyramidal geometry by two ni trogen atoms of one phen and the amino nitrogen atom ,one carboxylate oxygen atom of L-met in the base plane,and an aqua at t he apical position.A one-dimension al chain configuration formed by the hydrogen-bonding and weak Cu-O(the uncoordinated carboxyl oxygen a tom)coordination interactions be-tween neighboring[Cu(L-met)(phen)(H 2 O)] + cations.CCDC:183368.
