As important biocatalysts, nitrilases can efficiently convert nitrile groups into acids and ammonia in a mild and eco-friendly manner, being widely used in the synthesis of important pharmaceutical intermediates. Early studies reported that nitrilases only had the hydrolysis activity of catalyzing the formation of corresponding carboxylic acid products from nitriles, showing catalytic specificity. However, recent studies have shown that some nitrilases exhibit the hydration activity for catalyzing the formation of amides from nitriles, showing catalytic promiscuity. The catalytic promiscuity of nitrilases has dual effects. On the one hand, the presence of amide by-products increases the difficulties and costs of subsequent separation and purification of carboxylic acid products. On the other hand, however, if the catalytic reaction pathways of nitrilases can be precisely regulated to reshape enzyme functions, the reactions catalyzed by nitrilases can be broadened to provide new ideas for the biosynthesis of high-value amides, which is crucial for the development of artificial enzymes and biocatalysis. This review summarized the research progress in the catalytic promiscuity of nitrilases and discussed the key regulatory factors that may affect the catalytic promiscuity of nitrilases from the evolutionary origin, catalytic domains, and catalytic mechanisms, hoping to provide reference and inspiration for the application of nitrilases in biocatalysis.
Aminohydrolases/chemistry* ; Biocatalysis ; Nitriles/chemistry* ; Substrate Specificity ; Catalytic Domain ; Catalysis

We produced (S)-4-cyano-3-(4-chlorophenyl)-butyrate by highly stereoselective biocatalyst in this study. A nitrilase-producing strain, named Gibberella intermedia WX12, was isolated by 3-(4-chlorophenyl)-glutaronitrile as substrate in the screening with phenol-sodium hypochlorite method. The fermentation conditions and catalytic properties of this strain were investigated. The preferred carbon and nitrogen sources for nitrilase production were lactose (30 g/L) and peptone (20 g/L). After being cultivated for 96 h, the cells were collected for use in biotransformation. The hydrolysis of 3-(4-chlorophenyl)-glutaronitrile was performed at 30 degrees C in phosphate buffer (pH 8.0, 50 mmol/L) for 24 h to give (S)-4-cyano-3-(4-chlorophenyl)-butyric acid with 90% yield and > 99% of ee, which can be used for the synthesis of (R)- and (S)-baclofen. The configuration of product was determined by chemically converting it to baclofen and comparison with the authentic sample by chiral HPLC analysis.
Aminohydrolases ; metabolism ; Baclofen ; chemical synthesis ; chemistry ; Biocatalysis ; Chlorophenols ; chemistry ; Gibberella ; enzymology ; Hydrolysis ; Nitriles ; chemistry ; Prodrugs ; chemical synthesis ; chemistry

Nitriles are an important type of synthetic intermediates in the production of fine chemicals because of their easy preparations and versatile transformations. The traditional chemical conversion of nitriles to carboxylic acids and amides is feasible but it requires relatively harsh conditions of heat, acid or alkali. Nitrile converting enzymes (nitrilase, nitrile hydratase and amidase) which are used as biocatalyst for the production of fine chemicals have attracted substantial interest because of their ability to convert readily available nitriles into the corresponding higher value amides or acids under mild conditions with excellent chemo-, regio- and stereo-selectivities. Many nitrile converting enzymes have been explored and widely used for the production of fine chemicals. In this paper, various examples of biocatalytic synthesis of pharmaceuticals and their intermediates, agrochemicals and their intermediates, food and feed additives, and other fine chemicals are presented. In the near future, an increasing number of novel nitrile converting enzymes will be screened and their potential in the production of useful fine chemicals will be further exploited.
Amides ; metabolism ; Amidohydrolases ; metabolism ; Aminohydrolases ; metabolism ; Carboxylic Acids ; metabolism ; Chemical Industry ; methods ; Hydro-Lyases ; metabolism ; Nitriles ; chemistry