Fad type glutamate dehydrogenase

An FAD type glutamate dehydrogenase, wherein

• the amino acid at the position corresponding to the 109th position of SEQ ID NO:
• 58 is substituted with an amino acid residue selected from the group consisting of serine, tryptophan, glutamine, alanine, aspartic acid, glutamic acid, phenylalanine, arginine, histidine, lysine, threonine, asparagine, cysteine, glycine, proline, valine, leucine, isoleucine, and tyrosine, the amino acid at the position corresponding to the 545th position of SEQ ID NO:
• 58 is substituted with an amino acid residue selected from the group consisting of alanine, aspartic acid, glutamic acid, phenylalanine, arginine, histidine, lysine, serine, threonine, asparagine, glutamine, cysteine, glycine, proline, valine, isoleucine, methionine, tyrosine and tryptophan and/or the amino acid at the position corresponding to the 425th position of SEQ ID NO:
• 58 is substituted with an amino acid residue selected from the group consisting of glutamine, alanine, aspartic acid, glutamic acid, phenylalanine, arginine, histidine, lysine, serine, threonine, asparagine, cysteine, glycine, proline, valine, isoleucine, methionine, tyrosine and tryptophan and the ratio (OD/DH) of oxidase activity (OD) to dehydrogenase activity (DH) of the polypeptide after the amino acid substitution is reduced compared to the polypeptide prior to the amino acid substitution,
• wherein the FAD type glutamate dehydrogenase further comprises a thermal stability improving mutation, whereby the thermal stability of the polypeptide after the amino acid substitution is improved compared to the polypeptide before the substitution, and
• the FAD type glutamate dehydrogenase meets a condition selected from the group consisting of the following:
• (i) when the amino acid sequence of the glutamate dehydrogenase is aligned with the amino acid sequence of SEQ ID NO:
• 58, the glutamate dehydrogenase comprises a substitution of the amino acid at the position corresponding to a position selected from the group consisting of the 186th, 87th, 103rd, 133rd, 297th, 376th, 393rd, 428th, 516th, 566th, 568th, 585th, and 615th positions of SEQ ID NO:
• 58,
• (ii) the glutamate dehydrogenase of said (i), wherein the glutamate dehydrogenase consists of an amino acid sequence comprising a substitution, deletion or addition of one or several amino acids at a position other than the positions corresponding to the 186th, 87th, 103rd, 133rd, 297th, 376th, 393rd, 428th, 516th, 566th, 568th, 585th, and 615th positions of SEQ ID NO:
• 58,
• (iii) with regard to the glutamate dehydrogenase of said (i) or (ii), the full length amino acid sequence thereof comprises an amino acid sequence identity of 70% or more, 80% or more, or 90% or more with the amino acid sequence of SEQ ID NO:
• 58 or SEQ ID NO:
• 1, and
• (iv) with regard to the glutamate dehydrogenase of said (i) or (ii), the full length amino acid sequence thereof comprises an amino acid sequence identity of 70% or more, 80% or more, or 90% or more with the amino acid sequence of SEQ ID NO:
• 58 or SEQ ID NO:
• 1, the amino acid at the position corresponding to the 291st position of SEQ ID NO:
• 58 in the glutamate dehydrogenase is arginine, and the amino acid sequence of the positions corresponding to the 51st to 56th positions of SEQ ID NO:
• 58 is Gly-Xaa-Gly-Xaa-Xaa-Gly (wherein Xaa represents any amino acid).