Purification and characterization of the enantioselective nitrile hydratase from Rhodococcus equi A4

Abstract

The nitrile hydratase from Rhodococcus equi A4 consisted of two kinds of subunits which slightly differed in molecular weight (both approximately 25 kDa) and showed a significant similarity in the N-terminal amino acid sequences to those of the nitrile hydratase from Rhodococcus sp. N-774. The enzyme preferentially hydrated the S-isomers of racemic 2-(2-, 4-methoxyphenyl)propionitrile, 2-(4-chlorophenyl)propionitrile and 2-(6-methoxynaphthyl)propionitrile (naproxennitrile) with E-values of 5-15. The enzyme functioned in the presence of 5-98% (v/v) of different hydrocarbons, alcohols or diisopropyl ether. The addition of 5% (v/v) of n-hexane, n-heptane, isooctane, n-hexadecane, pristane and methanol increased the E-value for the enzymatic hydration of 2-(6-methoxynaphthyl)propionitrile.

Nitrilase‐ and Nitrile Hydratase‐Catalyzed Enantioselective Preparation of Non‐Proteinogenic Amino Acids

“…In contrast, fi ve -membered trans -amide 1b was obtained in very high enantiopurity, but not so its acid [34] . The high enantiomeric purity of the remaining trans -nitriles 1a and 3a is remarkable in view of the extent of conversion (38 and 24%, respectively).This can be attributed to the reportedly high enantioselectivity of the nitrile hydratase from R. erythropolis A4 for the transformation of ( ± ) -1a to 1b at the least [40] .…”

Enzymatic production of 2-amino-2,3-dimethylbutyramide by cyanide-resistant nitrile hydratase

“…n-hexane was reported to be beneWt for bioconversion of naproxen nitrile by NHase of Rhodococcus sp. C3II [9], but harmful for hydration of the same substrate using NHase from R. equi A4 [24]. These results suggested that eVect of co-solvent on NHase activity was likely to be dependent on the source of NHase.…”

“…To date, successful use of biphasic system using waterimmiscible organic solvent in NHase-catalyzed biotransformation remained scarce. n-hexane and isooctane were applied to the biocatalytic hydration of aromatic nitrile (naproxen nitrile) [9,24]. This study was the Wrst report regarding biphasic methodology used in NHase-mediated hydration of aliphatic nitrile.…”

Biotransformation of heterocyclic dinitriles by Rhodococcus erythropolis and fungal nitrilases

“…The nitrile hydratase was partially purified as described by Přepechalová et al (2001). The nitrilases from Aspergillus niger CCF 3411 (Culture Collection of Fungi, Charles University Prague, Czech Republic) and Fusarium solani CCF 3635 were used as a semi-purified enzyme ) and a cell-free extract (Vejvoda , respectively.…”

“…Different immobilized formulations of the nitrilase from Fusarium solani were also highly active towards the above nitriles ). In addition, a nitrile hydratase from Rhodococcus erythropolis A4 (formerly R. equi A4) was useful for the preparation of amides from heterocyclic nitriles like cyanopyridines (Přepechalová et al 2001).…”