93939-74-3Relevant articles and documents
RETRACTED ARTICLE: Chemoenzymatic Method for Enantioselective Synthesis of (R)-2-Phenylglycine and (R)-2-Phenylglycine Amide from Benzaldehyde and KCN Using Difference of Enzyme Affinity to the Enantiomers
Kawahara, Nobuhiro,Asano, Yasuhisa
, p. 5014 - 5020 (2018/10/20)
In general, enzymatic and chemoenzymatic methods for asymmetric synthesis of α-amino acids are performed using highly enantioselective enzymes. The enzymatic reactions using α-aminonitrile as a starting material have been performed using reaction conditions apart from the chemical Strecker synthesis. We developed a new chemoenzymatic method for the asymmetric synthesis of α-amino acids from aldehydes and KCN by performing Strecker synthesis and nitrilase reaction in the same reaction mixture. Nitrilase AY487533 that showed rather low enantioselectivity in hydrolysis of 2-phenylglycinonitrile (2PGN) to 2-phenylglycine (2PG) was utilized in the hydrolysis of aminonitrile formed from benzaldehyde and KCN via 2PGN by Strecker synthesis, preferentially synthesizing (R)-2PG with more than 95 % yield and enantiomeric excess (ee). The method was also utilized for the synthesis of (R)-2-phenylglycine amide ((R)-2PGNH2) from benzaldehyde and KCN by the chemoenzymatic reaction in the presence of a mutated nitrilase AY487533W186A, which catalyzes the conversion of 2PGN to 2PGNH2.
Nitrilases, nucleic acids encoding them and methods for making and using them
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Page/Page column 89; 90, (2016/01/09)
The invention relates to nitrilases and to nucleic acids encoding the nitrilases. In addition methods of designing new nitrilases and method of use thereof are also provided. The nitrilases have increased activity and stability at increased pH and temperature.
Enzymatic synthesis of chiral phenylalanine derivatives by a dynamic kinetic resolution of corresponding amide and nitrile substrates with a multi-enzyme system
Yasukawa, Kazuyuki,Asano, Yasuhisa
, p. 3327 - 3332 (2013/01/15)
Mutant α-amino-ε-caprolactam (ACL) racemase (L19V/L78T) from Achromobacter obae with improved substrate specificity toward phenylalaninamide was obtained by directed evolution. The mutant ACL racemase and thermostable mutant D-amino acid amidase (DaaA) from Ochrobactrum anthropi SV3 co-expressed in Escherichia coli (pACLmut/pDBFB40) were utilized for synthesis of (R)-phenylalanine and non-natural (R)-phenylalanine derivatives (4-OH, 4-F, 3-F, and 2-F-Phe) by dynamic kinetic resolution (DKR). Recombinant E. coli with DaaA and mutant ACL racemase genes catalyzed the synthesis of (R)-phenylalanine with 84% yield and 99% ee from (RS)-phenylalaninamide (400 mM) in 22 h. (R)-Tyrosine and 4-fluoro-(R)-phenylalanine were also efficiently synthesized from the corresponding amide compounds. We also co-expresed two genes encoding mutant ACL racemase and L-amino acid amidase from Brevundimonas diminuta in E. coli and performed the efficient production of various (S)-phenylalanine derivatives. Moreover, 2-aminophenylpropionitrile was converted to (R)-phenylalanine by DKR using a combination of the non-stereoselective nitrile hydratase from recombinamt E. coli and mutant ACL racemase and DaaA from E. coli encoding mutant ACL racemase and DaaA genes. Copyright
