Nitrilases unsaturated nitriles

Effenberger, F. and Oswald, S. 2001b. (i )-Selective hydrolysis of (ii,Z)-a,P-unsaturated nitriles by the recombinant nitrilase AtNITl from Arabidopsis thaliana. Tetrahedron ... 

Among aliphatic nitriles, unbranched saturatured or unsaturated compounds with a medium chain length (for instance, propionitrile, butyronitrile, hexaneni-trile, and acrylonitrile) are hydrolyzed with the highest relative rate (about 20-35% of that for benzonitrile) by aromatic nitrilases. Branched nitriles are in general poor substrates of these enzymes but, for instance, isobutyronitrile is one of the best substrates of the aliphatic nitrilase from R. rhodochrous K22 [28]. 

The majority of aromatic nitrilases hydrolyze not only (hetero) aromatic but also aliphatic saturated or unsaturated nitriles (Table 12.2). The ability of some of the enzymes to hydrolyze acrylonitrile has an industrial impact, as it enables the synthesis of acrylic acid (a polymer building block), the elimination of acrylonitrile from wastewaters [73], or the construction of acrylonitrile biosensors [74]. The nitrilase from R. rhodochrous J1 required activation by ammonium sulfate prior to use for the transformation of acrylonitrile. This activation resided in a rearrangement of the enzyme s quaternary structure, resulting in an increase in molecular weight from... 

Aromatic, heterocyclic, and certain unsaturated aliphatic nitriles are often directly hydrolyzed to the corresponding acids without formation of the intermediate free amide by a so-called nitrilase enzyme. The nitrile hydratase and nitrilase enzyme use distinctively different mechanisms of action. 

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