Abstract: The invention is directed to a protein comprising the amino acid sequence represented by SEQ ID NO: 1; a protein comprising an amino acid sequence with one to ten amino acid deletions, substitutions, or additions in the amino acid sequence represented by SEQ ID NO: 1, and having fructosyl peptide oxidase activity; a protein comprising an amino acid sequence having 99% or higher homology to the amino acid sequence represented by SEQ ID NO: 1, and having fructosyl peptide oxidase activity; and a protein having fructosyl peptide oxidase activity, which is encoded by an expression plasmid harbored by the Escherichia coli XL1-Blue MRF? strain deposited under Accession No. FERM BP-11026; as well as uses of such proteins.