Patent ID: 7419813

Claim:
An isolated or purified polypeptide which: (a) exhibits fructosyl peptide oxidase activity which acts on fructosyl valyl histidine in the presence of oxygen and catalyze a reaction that produces α-ketoaldehyde, valyl histidine and hydrogen peroxide; (b) exhibits optimal fructosyl peptide oxidase activity of (a) within the range of pH 6.0-8.0; (c) exhibits the fructosyl peptide oxidase activity of (a) within the temperature range of 20-45° C.; (d) retains at least 80% of said fructosyl peptide oxidase activity of (a) following a heat treatment at 45° C. for 10 minutes; and (e) is stable within the range of pH 6.0-9.0, and which is selected from the group consisting of: (x) a polypeptide comprising the entire amino acid sequence of SEQ ID NO: 1; (y) a polypeptide comprising SEQ ID NO: 1, but having the deletion, substitution and/or addition of one to twenty amino acids relative to the amino acid sequence of SEQ ID NO: 1; and (z) a polypeptide comprising an amino acid sequence having at least 95% homology with the amino acid sequence of SEQ ID NO: 1.