To obtain improved type halohydrin epoxidases in which stereoselectivity, product inhibition resistance, etc., are improved, and provide a method for efficiently producing an optically active epihalohydrin or a 4-halo-3-hydroxybutyronitrile by utilizing them.
In the amino acid sequence of a wild type halohydrin epoxidase consisting of a specific amino acid sequence, the improved type halohydrin epoxidases of which second Ala is substituted with Lys and introducing at least one kind of amino acid mutation selected from the following (i) to (l), are provided. (i) The amino acid mutation in which 29th Glu is substituted with Lys, (j) the amino acid mutation in which 179th Glu is substituted with Gln, (k) the amino acid mutation in which both 183th Asp and 184th Met are substituted with Val, and (l) the amino acid mutation in which 221th Phe is substituted with Leu.
TO FUJIO
AKIYAMA TAKAMICHI
Keiko Kanemoto
Koji Morita
Reiko Tanaka
Yuko Matsuniya
Ken Kitano
Natsuki Ito