22951-96-8Relevant articles and documents
Artificial Biocatalytic Cascade with Three Enzymes in One Pot for Asymmetric Synthesis of Chiral Unnatural Amino Acids
Zhou, Haisheng,Meng, Lijun,Yin, Xinjian,Liu, Yayun,Xu, Gang,Wu, Jianping,Wu, Mianbin,Yang, Lirong
supporting information, p. 6470 - 6477 (2019/11/02)
Two biocatalytic reactions, transamination catalyzed by transaminases and reductive amination catalyzed by amino acid dehydrogenases, can be used for asymmetric synthesis of optically pure unnatural amino acids. However, although transaminases show a great diversity and broad substrate spectrum, most transaminase reactions are reversible, while amino acid dehydrogenases catalyze reductive amination irreversibly but with strict substrate specificity. Accordingly, herein we developed a tri-enzyme one-pot reaction system to exploit the respective advantages of transaminases and amino acid dehydrogenases, while overcoming the disadvantages of each. In this work, representatives of all four subgroups of transaminases coupled with different amino acid dehydrogenases to produce five l- and four d- unnatural amino acid products, using ammonia and the co-enzyme NAD(P)H, which is regenerated by a robust alcohol dehydrogenase with 2-propanol as cheap cosubstrate. The complete conversion and high enantiopurity (ee > 99 %) of the products, demonstrated it as an ideal alternative for asymmetric synthesis of chiral amino acid compounds.
Influence of the aromatic moiety in α- And β-arylalanines on their biotransformation with phenylalanine 2,3-aminomutase from: Pantoea agglomerans
Varga, Andrea,Bánóczi, Gergely,Nagy, Botond,Bencze, László Csaba,To?a, Monica Ioana,Gellért, ákos,Irimie, Florin Dan,Rétey, János,Poppe, László,Paizs, Csaba
, p. 56412 - 56420 (2016/07/06)
In this study enantiomer selective isomerization of various racemic α- and β-arylalanines catalysed by phenylalanine 2,3-aminomutase from Pantoea agglomerans (PaPAM) was investigated. Both α- and β-arylalanines were accepted as substrates when the aryl moiety was relatively small, like phenyl, 2-, 3-, 4-fluorophenyl or thiophen-2-yl. While 2-substituted α-phenylalanines bearing bulky electron withdrawing substituents did not react, the corresponding substituted β-aryl analogues were converted rapidly. Conversion of 3- and 4-substituted α-arylalanines happened smoothly, while conversion of the corresponding β-arylalanines was poor or non-existent. In the range of pH 7-9 there was no significant influence on the conversion of racemic α- or β-(thiophen-2-yl)alanines, whereas increasing the concentration of ammonia (ammonium carbonate from 50 to 1000 mM) inhibited the isomerization progressively and decreased the amount of the by-product (i.e. (E)-3-(thiophen-2-yl)acrylic acid was detected). In all cases, the high ee values of the products indicated excellent enantiomer selectivity and stereospecificity of the isomerization except for (S)-2-nitro-α-phenylalanine (ee 92%) from the β-isomer. Substituent effects were rationalized by computational modelling revealing that one of the main factors controlling biocatalytic activity was the energy difference between the covalent regioisomeric enzyme-substrate complexes.
Bisepoxide cross-linked enzyme aggregates - New immobilized biocatalysts for selective biotransformations
Weiser, Diana,Varga, Andrea,Kovacs, Klaudia,Nagy, Flora,Szilagyi, Andras,Vertessy, Beata G.,Paizs, Csaba,Poppe, Laszlo
, p. 1463 - 1469 (2014/05/20)
Glycerol diglycidyl ether (GDE) is a convenient and inexpensive bisepoxide cross-linker as demonstrated by the preparation of cross-linked enzyme aggregates (CLEAs) from two enzyme classes. The GDE CLEAs of lipase from Pseudomonas fluorescens (AK), lipase from Burkholderia cepacia (PS), and lipase B from Candida antarctica (CaL B) as well as of phenylalanine ammonia-lyase (PAL) from Petroselinum crispum demonstrated improved properties as compared with their glutaraldehyde (GA) cross-linked counterparts. Ultrasonication studies indicated that the GDE CLEAs of lipase PS and PAL were mechanically more stable than the GA CLEAs. In the kinetic resolution of rac-1-phenylethanol, the catalytic activity of the GDE-lipase CLEAs (U=69.6, 134.8, and 127.4 U g -1 for AK, CaL B, and PS prepared at 22 °C, respectively) surpassed that of the corresponding GA-lipase CLEAs (U=24.4, 131.0, and 119.2 U g-1 for AK, CaL B, and PS prepared at 22 °C, respectively). The GDE co-CLEAs from PAL and bovine serum albumin (BSA) could be recycled at least three times if used for the stereoselective ammonia addition in 6 M ammonia to (E)-3-(thiophen-2-yl)acrylic acid, whereas the recycling of the conventional GA-PAL CLEAs from this medium failed. The missing linker: Glycerol diglycidyl ether is applied as a cross-linker for cross-linked enzyme aggregates (CLEAs) of various enzymes such as lipases and phenylalanine ammonia lyases. The bisepoxide CLEAs prove to be efficient and robust biocatalysts surpassing the performance of the glutaraldehyde CLEAs.
