1991-86-2Relevant articles and documents
A novel phenylalanine ammonia-lyase from Pseudozyma antarctica for stereoselective biotransformations of unnatural amino acids
Varga, Andrea,Csuka, Pál,Sonesouphap, Orlavanah,Bánóczi, Gergely,To?a, Monica Ioana,Katona, Gabriel,Molnár, Zsófia,Bencze, László Csaba,Poppe, László,Paizs, Csaba
, p. 185 - 194 (2020/04/28)
A novel phenylalanine ammonia-lyase of the psychrophilic yeast Pseudozyma antarctica (PzaPAL) was identified by screening microbial genomes against known PAL sequences. PzaPAL has a significantly different substrate binding pocket with an extended loop (26 aa long) connected to the aromatic ring binding region of the active site as compared to the known PALs from eukaryotes. The general properties of recombinant PzaPAL expressed in E. coli were characterized including kinetic features of this novel PAL with L-phenylalanine (S)-1a and further racemic substituted phenylalanines rac-1b-g,k. In most cases, PzaPAL revealed significantly higher turnover numbers than the PAL from Petroselinum crispum (PcPAL). Finally, the biocatalytic performance of PzaPAL and PcPAL was compared in the kinetic resolutions of racemic phenylalanine derivatives (rac-1a-s) by enzymatic ammonia elimination and also in the enantiotope selective ammonia addition reactions to cinnamic acid derivatives (2a-s). The enantiotope selectivity of PzaPAL with o-, m-, p-fluoro-, o-, p-chloro- and o-, m-bromo-substituted cinnamic acids proved to be higher than that of PcPAL.
One-Pot Enzymatic Synthesis of d-Arylalanines Using Phenylalanine Ammonia Lyase and l-Amino Acid Deaminase
Zhu, Longbao,Feng, Guoqiang,Ge, Fei,Song, Ping,Wang, Taotao,Liu, Yi,Tao, Yugui,Zhou, Zhemin
, p. 1 - 15 (2018/06/11)
The phenylalanine ammonia-lyase (AvPAL) from Anabaena variabilis catalyzes the amination of substituent trans-cinnamic acid (t-CA) to produce racemic d,l-enantiomer arylalanine mixture owing to its low stereoselectivity. To produce high optically pure d-arylalanine, a modified AvPAL with high d-selectivity is expected. Based on the analyses of catalytic mechanism and structure, the Asn347 residue in the active site was proposed to control stereoselectivity. Therefore, Asn347 was mutated to construct mutant AvPAL-N347A, the stereoselectivity of AvPAL-N347A for d-enantiomer arylalanine was 2.3-fold higher than that of wild-type AvPAL (WtPAL). Furthermore, the residual l-enantiomer product in reaction solution could be converted into the d-enantiomer product through stereoselective oxidation by PmLAAD and nonselective reduction by reducing agent NH3BH3. At optimal conditions, the conversion rate of t-CA and optical purity (enantiomeric excess (eeD)) of d-phenylalanine reached 82% and exceeded 99%, respectively. The two enzymes displayed activity toward a broad range of substrate and could be used to efficiently synthesize d-arylalanine with different groups on the phenyl ring. Among these d-arylalanines, the yield of m-nitro-d-phenylalanine was highest and reached 96%, and the eeD exceeded 99%. This one-pot synthesis using AvPAL and PmLAAD has prospects for industrial application.
Organocatalytic Enantioselective Addition of α-Aminoalkyl Radicals to Isoquinolines
Liu, Xiangyuan,Liu, Yang,Chai, Guobi,Qiao, Baokun,Zhao, Xiaowei,Jiang, Zhiyong
supporting information, p. 6298 - 6301 (2018/10/09)
With a dual organocatalytic system involving a chiral phosphoric acid and a dicyanopyrazine-derived chromophore (DPZ) photosensitizer and under the irradiation with visible light, an enantioselective Minisci-type addition of α-amino acid-derived redox-active esters (RAEs) to isoquinolines has been developed. A variety of prochiral α-aminoalkyl radicals generated from RAEs were successfully introduced on isoquinolines, providing a range of valuable α-isoquinoline-substituted chiral secondary amines in high yields with good to excellent enantioselectivities.
