A mutated enzyme having an increased ratio of glucose dehydrogenase to glucose oxidase activity compared to the enzyme before mutation, comprising an amino acid sequence, wherein at least one amino acid selected from the group consisting of,, and is substituted with another amino acid in an amino acid sequence of a microorganism-derived glucose oxidase: the amino acid corresponding to the amino acid at position 132 of the amino acid sequence of SEQ ID NO: 1; the amino acid corresponding to the amino acid at position 353 of the amino acid sequence of SEQ ID NO: 1; the amino acid corresponding to the amino acid at position 446 of the amino acid sequence of SEQ ID NO: 1; and the amino acid corresponding to the amino acid at position 582 of the amino acid sequence of SEQ ID NO: 1; wherein at least (i) the amino acid, the amino acid, the amino acid or the amino acid, or a combination of at least two amino acids selected from these amino acids; or (ii) the amino acid, the amino acid or the amino acid, or a combination of at least two amino acids selected from these amino acids; and/or (iii) the amino acid and the amino acid are substituted; wherein the amino acid sequence of a microorganism-derived glucose oxidase is the amino acid sequence of SEQ ID NO: 1 or 2; wherein (a) the amino acid after substitution is: alanine for the amino acid; alanine for the amino acid; histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid; and/or (b) the amino acid after substitution is: alanine for the amino acid; histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid, and/or (c) the amino acid after substitution is: histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid; and wherein the identity of the amino acid sequence of the mutated enzyme to the amino acid sequence of SEQ ID NO: 1 or 2 wherein one or more amino acids of,, or are mutated is 90 % or more. the amino acid corresponding to the amino acid at position 132 of the amino acid sequence of SEQ ID NO: 1; the amino acid corresponding to the amino acid at position 353 of the amino acid sequence of SEQ ID NO: 1; the amino acid corresponding to the amino acid at position 446 of the amino acid sequence of SEQ ID NO: 1; and the amino acid corresponding to the amino acid at position 582 of the amino acid sequence of SEQ ID NO: 1; wherein at least (i) the amino acid, the amino acid, the amino acid or the amino acid, or a combination of at least two amino acids selected from these amino acids; or (ii) the amino acid, the amino acid or the amino acid, or a combination of at least two amino acids selected from these amino acids; and/or (iii) the amino acid and the amino acid are substituted; wherein the amino acid sequence of a microorganism-derived glucose oxidase is the amino acid sequence of SEQ ID NO: 1 or 2; wherein (a) the amino acid after substitution is: alanine for the amino acid; alanine for the amino acid; histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid; and/or (b) the amino acid after substitution is: alanine for the amino acid; histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid, and/or (c) the amino acid after substitution is: histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid; and wherein the identity of the amino acid sequence of the mutated enzyme to the amino acid sequence of SEQ ID NO: 1 or 2 wherein one or more amino acids of,, or are mutated is 90 % or more. (i) the amino acid, the amino acid, the amino acid or the amino acid, or a combination of at least two amino acids selected from these amino acids; or (ii) the amino acid, the amino acid or the amino acid, or a combination of at least two amino acids selected from these amino acids; and/or (iii) the amino acid and the amino acid are substituted; wherein the amino acid sequence of a microorganism-derived glucose oxidase is the amino acid sequence of SEQ ID NO: 1 or 2; wherein (a) the amino acid after substitution is: alanine for the amino acid; alanine for the amino acid; histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid; and/or (b) the amino acid after substitution is: alanine for the amino acid; histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid, and/or (c) the amino acid after substitution is: histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid; and wherein the identity of the amino acid sequence of the mutated enzyme to the amino acid sequence of SEQ ID NO: 1 or 2 wherein one or more amino acids of,, or are mutated is 90 % or more. (a) the amino acid after substitution is: alanine for the amino acid; alanine for the amino acid; histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid; and/or (b) the amino acid after substitution is: alanine for the amino acid; histidine for the amino acid; and serine, arginine, leucine or proline for the amino acid, and/or (c) the amino acid after substitution is: histidine for the amino acid;