Nitrile hydratase variant

Pseudonocardia thermophila The amino acid sequence of a mutant which is obtained by introducing a novel mutation into a JCM3095-derived nitrile hydratase consisting of two types of heterogeneous subunits, and the base sequence of the gene are provided. The nitrile hydratase is modified by specifying the region to be modified in the stereostructure/amino acid sequence of the nitrile hydratase, and applying alteration such as substitution, insertion, deletion or the like, to the amino acids in the amino acid sequence which are corresponding to the amino acid residues forming the region. Also provided is a method for modifying an enzyme having a nitrile hydratase activity.