Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic a...Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic anhydride and succinic anhydride separately.We found that both the hydrolytic activity and the thermal stability of the modified Novozym-435 were enhanced compared with the unmodified enzyme.The modified Novozym-435 catalysts were used to synthesize the succinate derivative of vitamin E.Compared with the native Novozym-435,the catalytic activity of the modified novozym-435 in promoting the synthesis of vitamin E succinate was dramatically increased,with the novozym-435 modified with succinic anhydride（N435-S）as the most active catalyst.Conditions for the synthesis of vitamin E succinate were also optimized.A mixture of tert-butanol and DMSO（volume ratio of 2︰3）was the most suitable medium for the reaction,whereas the appropriate molar ratio of vitamin E to succinic anhydride and reaction temperature were 1︰5 and 40°C,respectively.Under these reaction conditions,the yield of vitamin E succinate reached 94.4%.N435-S could be reused for five batches.展开更多
As a small catalytic DNA molecule, 10-23 DNAzyme has cleavage ability against complementary RNA. Previous studies of chemical modification have shown that its catalytic core can be further optimized in order to obtain...As a small catalytic DNA molecule, 10-23 DNAzyme has cleavage ability against complementary RNA. Previous studies of chemical modification have shown that its catalytic core can be further optimized in order to obtain more powerful catalytic ability. The analogues of 2＇-deoxyadenosine （5） and 2＇-deoxyguanosine （6） could improve the cleavage ability of the DNAzyme when positioned at positions A9, （32 and G14 in the catalytic core, respectively. Moreover, their combinatorial incorporations were studied, the results implicated that the effect was position-dependent, and positive additive results could be achieved at some positions. The highly conserved G1, G2 and G14 could be optimized by single or combinatorial modification with 2＇-deoxyguanosine analogues. Chemical modifications on the functional groups of the core residues would be a feasible approach for the optimization of 10-23 DNAzyme.展开更多
基金Supported by the Fundamental Research Funds for the Central Universities and the State Key Development Program for Basic Research of China(2007CB714304)
文摘Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic anhydride and succinic anhydride separately.We found that both the hydrolytic activity and the thermal stability of the modified Novozym-435 were enhanced compared with the unmodified enzyme.The modified Novozym-435 catalysts were used to synthesize the succinate derivative of vitamin E.Compared with the native Novozym-435,the catalytic activity of the modified novozym-435 in promoting the synthesis of vitamin E succinate was dramatically increased,with the novozym-435 modified with succinic anhydride（N435-S）as the most active catalyst.Conditions for the synthesis of vitamin E succinate were also optimized.A mixture of tert-butanol and DMSO（volume ratio of 2︰3）was the most suitable medium for the reaction,whereas the appropriate molar ratio of vitamin E to succinic anhydride and reaction temperature were 1︰5 and 40°C,respectively.Under these reaction conditions,the yield of vitamin E succinate reached 94.4%.N435-S could be reused for five batches.
基金The National Natural Science Foundation of China(Grant No.21572268)
文摘As a small catalytic DNA molecule, 10-23 DNAzyme has cleavage ability against complementary RNA. Previous studies of chemical modification have shown that its catalytic core can be further optimized in order to obtain more powerful catalytic ability. The analogues of 2＇-deoxyadenosine （5） and 2＇-deoxyguanosine （6） could improve the cleavage ability of the DNAzyme when positioned at positions A9, （32 and G14 in the catalytic core, respectively. Moreover, their combinatorial incorporations were studied, the results implicated that the effect was position-dependent, and positive additive results could be achieved at some positions. The highly conserved G1, G2 and G14 could be optimized by single or combinatorial modification with 2＇-deoxyguanosine analogues. Chemical modifications on the functional groups of the core residues would be a feasible approach for the optimization of 10-23 DNAzyme.
