Modified amadoriase and method for producing the same, agent for improving surfactant resistance of amadoriase and composition for measuring HbA1c using the same

A modified amadoriase having improved residual activity (%) 5 minutes after an ionic surfactant is added compared with an amadoriase prior to the modification, and comprising

• (a) the amino acid sequence of SEQ ID No:
• 1, 3, or 37, said amino acid sequence further having a deletion, insertion, addition, and/or substitution of one to 15 amino acids in the amino acid sequence of SEQ ID No:
• 1, 3, or 37,or
• (b) an amino acid sequence having an identity of at least 90% with the amino acid sequence of SEQ ID No:
• 1, 3, or 37,
• wherein said modified amadoriase comprising the amino acid sequence of (a) or (b) comprises one or more substitution(s) selected from the group consisting of:
• (i) substitution of the amino acid at the position corresponding to position 257 of SEQ ID NO:
• 1 with cysteine, serine, or threonine,
• (ii) substitution of the amino acid at the position corresponding to position 262 of SEQ ID NO:
• 1 with histidine,
• (iii) substitution of the amino acid at the position corresponding to position 249 of SEQ ID NO:
• 1 with lysine, or arginine,
• (iv) substitution of the amino acid at the position corresponding to position 253 of SEQ ID NO:
• 1 with lysine, or arginine,
• (v) substitution of the amino acid at the position corresponding to position 337 of SEQ ID NO:
• 1 with lysine, or arginine,
• (vi) substitution of the amino acid at the position corresponding to position 340 of SEQ ID NO:
• 1 with proline,
• (vii) substitution of the amino acid at the position corresponding to position 232 of SEQ ID NO:
• 1 with lysine, or arginine,
• (viii) substitution of the amino acid at the position corresponding to position 129 of SEQ ID NO:
• 1 with lysine, or arginine,
• (ix) substitution of the amino acid at the position corresponding to position 132 of SEQ ID NO:
• 1 with lysine, or arginine,
• (x) substitution of the amino acid at the position corresponding to position 133 of SEQ ID NO:
• 1 with alanine, methionine, lysine, or arginine,
• (xi) substitution of the amino acid at the position corresponding to position 44 of SEQ ID NO:
• 1 with proline,
• (xii) substitution of the amino acid at the position corresponding to position 256 of SEQ ID NO:
• 1 with lysine, or arginine,
• (xiii) substitution of the amino acid at the position corresponding to position 231 of SEQ ID NO:
• 1 with lysine, or arginine, and
• (xiv) substitution of the amino acid at the position corresponding to position 81 of SEQ ID NO:
• 1 with lysine, or arginine.