mutation to a domain other than a preserved domain domains that are estimated not to influence the enzyme activity and temperature dependency even when a mutation is added to the amino acid sequence include domains located on a protein surface indicated from an x ray crystal structure of the protein examples of those domains include positions 1 to 40 111 to 190 213 to 310 340 to 397 420 to 435 455 to 492 514 to 538 and 552 to 572 the amino acid sequence of protein a2 is not particularly limited as long as it satisfies the requirements of the above described i to iii however the homology between the amino acid sequence of protein a2 and the amino acid sequence shown in seq id no 2 is preferably not smaller than 70 more preferably not smaller than 80 further preferably not smaller than 90 and particularly preferably not smaller than 95 it should be noted that an amino acid homology in the context of the present invention refers to an amino acid identity as a result of having any of the specific amino acids listed in the above described b protein a2 has a temperature dependency that is superior to that of the fadgdh of seq id no 2 among the specific amino acids listed in the above described b a preferable amino acid is any of the amino acids selected from the group consisting of 60c 60d 60l.