Method for quantitative determination of glycated protein and kit for quantitative determination of the same

A method for quantitative determination of a glycated protein, comprising (1) allowing a protease to act on a whole blood and/or blood cell sample to provide a mixture of proteolytic products of said sample, (2) allowing an elimination reagent containing at least two types of ketoamine oxidases to act on the mixture, eliminating therefrom an α-glycated amino acid, an ε-glycated amino acid, and an ε-glycated peptide, and then (3) determining an α-glycated peptide in the sample using oxidase that acts on the α-glycated peptide, wherein

• said types of ketoamine oxidases are selected from the group consisting of (i) an enzyme that acts on the α-glycated amino acid but does not act on the α-glycated peptide, (ii) an enzyme that acts on the ε-glycated amino acid and/or the ε-glycated peptide but does not act on the α-glycated peptide, and (iii) an enzyme that acts on the ε-glycated amino acid and/or the ε-glycated peptide and the α-glycated amino acid but does not act on the α-glycated peptide.