Enzymatic Preparation of an (S)-Amino Acid from a Racemic Amino Acid

Abstract

The (S)-amino acid, (S)-2-amino-3-(6-o-tolylpyridin-3-yl)propanoic acid (3), is a key intermediate needed for synthesis of an antidiabetic drug candidate. Three enzymatic routes to 3 were explored. (S)-Amino acid 3 could be prepared in 73% isolated yield with 99.9% ee from racemic amino acid 1 using (R)-amino acid oxidase from Trigonopsis Wariabilis expressed in Escherichia coli in combination with an (S)-aminotransferase using (S)-aspartate as amino donor. The (S)-aminotransferase was purified from a soil organism identified as Burkholderia sp. and cloned and expressed in E. coli. (S)-Amino acid 3 with 100% ee was also prepared in 68% solution yield and 54% isolated yield from 1 using recombinant (R)-amino acid oxidase from T. Wariabilis and an (S)-amino acid dehydrogenase from Sporosarcina ureae. The cofactor NADH required for the reductive amination reaction was regenerated using formate and formate dehydrogenase. The chemoenzymatic dynamic resolution of 1 by (R)-selective oxidation with Celite-immobilized (R)-amino acid oxidase in combination with chemical imine reduction using borane-ammonia complex gave an 81% solution yield and 68% isolated yield of 3 with 100% ee.

Why Leave a Job Half Done? Recent Progress in Enzymatic Deracemizations

“…[105] First, a recombinant amino acid oxidase from Trigonopsis variabilis provided the enantioselective oxidation of the (R)-amino acid leaving the (S)-antipode intact (Scheme 16a). Then, this keto acid was transformed into the desired (S)-amino acid by means of a reductive amination using whole cells from Sporosarcina ureae SC16048 containing an (S)-amino acid dehydrogenase.…”

“…[105] Using an oxidase and a TA Another related deracemization approach for the production of (S)-14 was based on the amino group oxidation to the corresponding keto derivative intermediate using the recombinant (R)-amino acid oxidase from T. variabilis, which was further aminated by a recombinant (S)-transaminase from Burkholderia sp.…”

“…[105] Using this strategy, the one-pot biotransformation could be done in buffer at 30 ºC. The applicability of this multienzymatic approach was shown by scaling up this bioprocess at 607 g of the racemic amino acid to obtain the enantiopure (S)-amino acid in 66% yield and >99% ee.…”

“…[105] In this case, (R Nowadays, there is a need for novel biocatalysts to cover new reactions or improve existing activities. In this sense, enzyme evolution to create new catalysts with desired functions is becoming an important tool in the last years.…”

Immobilization of Genetically-Modified d-Amino Acid Oxidase and Catalase on Carbon Nanotubes to Improve the Catalytic Efficiency

“…Cooperating with other enzymes, DAAOs promote the catalysis processes [16,17]. Under DAAOs catalysis, L-amino acids are obtained; they are key intermediates for the synthesis of pharmaceuticals [18].…”