Abstract: An R-3-aminobutyric acid preparation method with high efficiency and high stereoselectivity. The method comprises using aspartase with stereoisomerization catalytic activity derived from Escherichia coli to efficiently convert butenoic acid into R-3-aminobutyric acid. After only 24 h of reaction, the conversion rate is as high as ?98%, and the ee value is ?99.9%. The conversion efficiency is greatly improved, the reaction time is shortened, and the production costs are reduced. The method features a high yield, a high conversion rate, low costs, a short production cycle, a simple process, ease of enlargement, suitability for mass production and the like.

Abstract: The invention provides a highly active S-cyanohydrin lyase obtained by mutating an amino acid residue at position 103 of a wild-type cassava S-cyanohydrin lyase. The mutation can significantly increase an expression of a mutant enzyme in E. coli and does not require a decrease in temperature when induced. Further mutations at position 128 and other sites were performed to obtain mutants with increased catalytic activity.

Abstract: An R-3-aminobutyric acid preparation method with high efficiency and high stereoselectivity. The method comprises using aspartase with stereoisomerization catalytic activity derived from Escherichia coli to efficiently convert butenoic acid into R-3-aminobutyric acid. After only 24 h of reaction, the conversion rate is as high as ?98%, and the ee value is ?99.9%. The conversion efficiency is greatly improved, the reaction time is shortened, and the production costs are reduced. The method features a high yield, a high conversion rate, low costs, a short production cycle, a simple process, ease of enlargement, suitability for mass production and the like.

Abstract: An R-3-aminobutyric acid preparation method with high efficiency and high stereoselectivity. The method comprises using aspartase with stereoisomerization catalytic activity derived from Escherichia coli to efficiently convert butenoic acid into R-3-aminobutyric acid. After only 24 h of reaction, the conversion rate is as high as ?98%, and the ee value is ?99.9%. The conversion efficiency is greatly improved, the reaction time is shortened, and the production costs are reduced. The method features a high yield, a high conversion rate, low costs, a short production cycle, a simple process, ease of enlargement, suitability for mass production and the like.

Abstract: The invention provides a highly active S-cyanohydrin lyase obtained by mutating an amino acid residue at position 103 of a wild-type cassava S-cyanohydrin lyase. The mutation can significantly increase an expression of a mutant enzyme in E. coli and does not require a decrease in temperature when induced. Further mutations at position 128 and other sites were performed to obtain mutants with increased catalytic activity.

Abstract: The present invention relates to a novel use of a triterpenoid. In particular, the present invention provides a use of a compound of formula I, or an optical isomer thereof, or a racemate thereof, or a solvate thereof, or a pharmaceutically acceptable salt thereof, or a prodrug thereof in the preparation of a pharmaceutical composition or a preparation for preventing and/or treating ocular diseases caused by crystalline lens lesions. A novel finding of the present invention is that the compound of formula I can prevent and/or treat ocular diseases caused by crystalline lens lesions, such as prevention and treatment of cataracts, is safe, has low toxicity and few side effects, and has remarkable therapeutic efficacy and development and application prospects.

Abstract: An R-3-aminobutyric acid preparation method with high efficiency and high stereoselectivity. The method comprises using aspartase with stereoisomerization catalytic activity derived from Escherichia coli to efficiently convert butenoic acid into R-3-aminobutyric acid. After only 24 h of reaction, the conversion rate is as high as ?98%, and the ee value is ?99.9%. The conversion efficiency is greatly improved, the reaction time is shortened, and the production costs are reduced. The method features a high yield, a high conversion rate, low costs, a short production cycle, a simple process, ease of enlargement, suitability for mass production and the like.