A 3-branched asparagine-linked oligosaccharide derivative of the formula
(1) wherein the nitrogen of amino group of asparagine is modified with a
lipophilic protective group, biotin group or FITC group; a 3-branched
asparagine-linked oligosaccharide derivative which contains at least one
fucose in N-acetylglucosamine on the nonreducing terminal side of the
asparagine-linked oligosaccharide of the derivative; asparagine-linked
oligosaccharides and oligosaccharides thereof wherein Q is a lipophilic
protective group, biotin group or FITC group.