The invention provides a highly active S-cyanohydrin lyase obtained by mutating an amino acid residue at position 103 of a wild-type cassava S-cyanohydrin lyase. The mutation can significantly increase an expression of a mutant enzyme in E. coli and does not require a decrease in temperature when induced. Further mutations at position 128 and other sites were performed to obtain mutants with increased catalytic activity.

The invention provides a highly active S-cyanohydrin lyase obtained by mutating an amino acid residue at position 103 of a wild-type cassava S-cyanohydrin lyase. The mutation can significantly increase an expression of a mutant enzyme in E. coli and does not require a decrease in temperature when induced. Further mutations at position 128 and other sites were performed to obtain mutants with increased catalytic activity.

Provided are a method for obtaining an HNL gene and HNL derived from a millipede other than Chamberlinius hualienensis, and preparing a practically useable amount of HNL; and a method for producing optically active cyanohydrin using this HNL. A method for producing a millipede-derived HNL gene. A method that includes the selection of a gene having a base sequence that encodes a conserved amino acid sequence TAX1DIX2G (SEQ ID NO: 15) or VPNGDKIH (SEQ ID NO: 16) of millipede-derived HNL from genes present in an organism belonging to the Diplopoda. A protein having an amino acid sequence of any of (1)-(3) and having HNL activity. (1) An amino acid sequence listed in any of SEQ ID NOS: 1, 3, 5, 7, 9, 11, 13, 83, 85, 87, or 89; (2) an amino acid sequence having amino acids deleted, substituted, and/or added in an amino acid sequence of (1); or (3) an amino acid sequence having 90% or greater identity to an amino acid sequence of (1). A method for preparing optically active cyanohydrin by causing this millipede-derived HNL to act on a reaction solvent that contains an aldehyde or the like and a substance that generates hydrogen cyanide or the like.

Provided are a method for obtaining an HNL gene and HNL derived from a millipede other than Chamberlinius hualienensis, and preparing a practically useable amount of HNL; and a method for producing optically active cyanohydrin using this HNL. A method for producing a millipede-derived HNL gene. A method that includes the selection of a gene having a base sequence that encodes a conserved amino acid sequence TAX1DIX2G (SEQ ID NO: 15) or VPNGDKIH (SEQ ID NO: 16) of millipede-derived HNL from genes present in an organism belonging to the Diplopoda. A protein having an amino acid sequence of any of (1)-(3) and having HNL activity. (1) An amino acid sequence listed in any of SEQ ID NOS: 1, 3, 5, 7, 9, 11, 13, 83, 85, 87, or 89; (2) an amino acid sequence having amino acids deleted, substituted, and/or added in an amino acid sequence of (1); or (3) an amino acid sequence having 90% or greater identity to an amino acid sequence of (1). A method for preparing optically active cyanohydrin by causing this millipede-derived HNL to act on a reaction solvent that contains an aldehyde or the like and a substance that generates hydrogen cyanide or the like.

The objective of the present invention is to provide a (R)-hydroxynitrile lyase which is more stable than a hydroxynitrile lyase derived from a plant, a gene which encodes the hydroxynitrile lyase and by which heterologous expression is possible, and a method for producing the hydroxynitrile lyase. The (R)-hydroxynitrile lyase according to the present invention is characterized in having the specific amino acid sequence such as the amino acid sequence of SEQ ID NO: 3.

The present disclosure relates to a process for producing chiral -nitro alcohol compounds. The invention relates in particular to an (S)-selective oxynitrilase, which enantioselectively can catalyze the Henry reaction, wherein an aldehyde or ketone compound is converted to the corresponding -nitro alcohol compound in the presence of a nitroalkane compound and an oxynitrilase.

The present invention provides engineered nitroaldolase polypeptides useful for the production of the -nitro alcohols, as well as polynucleotides, compositions, and methods utilizing these engineered polypeptides.