- RETRACTED ARTICLE: Chemoenzymatic Method for Enantioselective Synthesis of (R)-2-Phenylglycine and (R)-2-Phenylglycine Amide from Benzaldehyde and KCN Using Difference of Enzyme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
-
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.
- Kawahara, Nobuhiro,Asano, Yasuhisa
-
p. 5014 - 5020
(2018/10/20)
-
- One-Pot Enantioselective Synthesis of d-Phenylglycines from Racemic Mandelic Acids, Styrenes, or Biobased l-Phenylalanine via Cascade Biocatalysis
-
Enantiopure d-phenylglycine and its derivatives are an important group of chiral amino acids with broad applications in thepharmaceutical industry. However, the existing synthetic methods for d-phenylglycine mainly rely on toxic cyanide chemistry and multistep processes. To provide green and safe alternatives, we envisaged cascade biocatalysis for the one-pot synthesis of d-phenylglycine from racemic mandelic acid, styrene, and biobased l-phenylalanine, respectively. Recombinant Escherichia coli (LZ110) was engineered to coexpress four enzymes to catalyze a 3-step reaction in one pot, transforming mandelic acid (210 mM) to give enantiopure d-phenylglycine in 29.5 g L?1 (195 mM) with 93% conversion. Using the same whole-cell catalyst, twelve other d-phenylglycine derivatives were also produced from the corresponding mandelic acid derivatives in high conversion (58–94%) and very high ee (93–99%). E. coli (LZ116) expressing seven enzymes was constructed for the transformation of styrene to enantiopure d-phenylglycine in 80% conversion via a one-pot 6-step cascade biotransformation. Twelve substituted d-phenylglycines were also produced from the corresponding styrene derivatives in high conversion (45–90%) and very high ee (92–99%) via the same cascade reactions. A nine-enzymeexpressing E. coli (LZ143) was engineered to transform biobased l-phenylalanine to enantiopure d-phenylglycine in 83% conversion via a one-pot 8-step transformation. Preparative biotransformations were also demonstrated. The high-yielding synthetic methods use cheap and green reagents (ammonia, glucose, and/or oxygen), and E. coli whole-cell catalysts, thus providing green and useful alternative methods for manufacturing d-phenylglycine. (Figure presented.).
- Zhou, Yi,Wu, Shuke,Li, Zhi
-
supporting information
p. 4305 - 4316
(2017/11/21)
-
- Nitrilases, nucleic acids encoding them and methods for making and using them
-
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.
- -
-
Page/Page column 89; 90
(2016/01/09)
-
- Nitrilases
-
The invention relates to nitrilases and to nucleic acids encoding the nitrilases. In addition, methods of designing new nitrilases and methods of use thereof are also provided. The nitrilases have increased activity and stability at increased pH and temperature.
- -
-
Paragraph 0495
(2015/09/22)
-
- Enzymatic synthesis of chiral phenylalanine derivatives by a dynamic kinetic resolution of corresponding amide and nitrile substrates with a multi-enzyme system
-
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
- Yasukawa, Kazuyuki,Asano, Yasuhisa
-
p. 3327 - 3332
(2013/01/15)
-
- Chemoenzymatic approaches to the dynamic kinetic asymmetric synthesis of aromatic amino acids
-
Enzymatic approaches for the production of amino acids by nitrilases are described. Dynamic kinetic asymmetric synthesis conditions were established for the aromatic aminonitriles, phenylglycinonitrile and 4- fluorophenylglycinonitrile, at high pH to produce the corresponding amino acid products in high enantiomeric excess. N-Acylation of aromatic aminonitriles led to spontaneous racemization at pH 8, allowing preferential enzymatic hydrolysis of the (R)-enantiomer to afford the product N-acylamino acids in up to 99% enantiomeric excess (ee).
- Chaplin, Jennifer A.,Levin, Michael D.,Morgan, Brian,Farid, Nancy,Li, Jen,Zhu, Zuolin,McQuaid, Jeff,Nicholson, Lawrence W.,Rand, Cynthia A.,Burk, Mark J.
-
p. 2793 - 2796
(2007/10/03)
-
- Dutch resolution of racemic 4-hydroxy- and 4-fluorophenylglycine with mixtures of phenylglycine and (+)-10-camphorsulfonic acid
-
4-Hydroxyphenylglycine and 4-fluorophenylglycine can be resolved with (+)-10-camphorsulfonic acid only if DL- or D-(-)-phenylglycine is added. When using DL-phenylglycine this is co-resolved in this process. In this resolution process mixed crystals are formed of the (+)-10-camphorsulfonic acid salts of the D-(-)-enantiomers of phenylglycine and the para substituted phenylglycines. In the crystal lattice of the mixed salts approximately 25- 30% of the D-(-)-phenylglycine molecules can be randomly replaced by D-(-)- para substituted phenylglycines, resulting in the desired resolution. The overall non-stoichiometric composition of the mixed crystals reflects to some extent the composition in solution. This behaviour is typical for solid solutions. The solid solution behaviour in this so called 'Dutch resolution' is proven by differential scanning calorimetry (DSC), X-ray crystal structure determination and powder diffraction. (C) 2000 Elsevier Science Ltd.
- Kaptein, Bernard,Elsenberg, Henk,Grimbergen, Reinier F. P.,Broxterman, Quirinus B.,Hulshof, Lumbertus A.,Pouwer, Kees L.,Vries, Ton R.
-
p. 1343 - 1351
(2007/10/03)
-
- Asymmetric synthesis of α-amino acids via diastereoselective addition of (R)-pantolactone to their ketenes
-
The diastereoselective addition of (R)-pantolactone to various amino ketenes derived from phthalylamino acids is reported. The configuration of the newly-generated asymmetric center is dependent on alkyl or aryl C(x substitution. This method constitutes a novel and convenient way of amino acid deracemization.
- Calmes, Monique,Daunis, Jacques,Mai, Nathalie
-
p. 1641 - 1648
(2007/10/03)
-
- HOMOCHIRAL HETEROORGANIC ANALOGS OF NATURAL COMPOUNDS. I. PREPARATIVE BIOCATALYTIC METHOD OF OBTAINING FLUORINE-CONTAINING L- AND D-PHENYLGLYCINES
-
A biocatalytic method of obtaining homochiral o- and p-fluorine-substituted phenylglycines by enantiomeric hydrolysis from N-phenylacetyl or N-acetyl derivatives under the action of Escherichia coli penicillin acylase or Streptoverticillium olivoreticuli aminoacylase is proposed.The L form of the amino acid and the unhydrolyzed D-enantiomer of the initial derivative are separated by extraction and chromatographic methods.The acid hydrolysis of the D-enantiomers of N-phenylacetyl derivatives of fluorine-substituted phenylglycines leads to partial (about 15percent) racemization.With a substantially higher (by two orders of magnitude) concentration of enzyme and an increase in the reaction time it is possible to use penicillinase as a catalyst for the hydrolysis of the D-enantiomer of the N-phenylacetyl derivative not accompanied by any appreciable racemization whatever.
- Soloshonok, V. A.,Galaev, I. Yu.,Shvyadas, V. K.,Kozlova, E. V.,Kotik, N. V.,et al.
-
p. 228 - 232
(2007/10/02)
-
- Synthesis of Optically Active Arylglycines by Photolysis of Optically Active (β-Hydroxyamino) Carbene-Chromium(0) Complexes
-
Photolysis of chromium complexes having the optically active amino alcohol (1R,2S)-(-)- or (1S,2R)-(+)-2-amino-1,2-diphenylethanol as the amino group produced aryl-substituted oxazinones in good yield with reasonable diastereoselectivity.Facile separation of diastereoisomers followed by mild reductive cleavage produced several arylglycines, having either electron-donating or withdrawing groups on the aromatic ring, in good overall yield and with excellent enantiomeric excess.
- Vernier, Jean-Michel,Hegedus, Louis S.,Miller, David B.
-
p. 6914 - 6920
(2007/10/02)
-