The invention relates to the use of deglycosylated detectors, especially secondary antibodies, for the determination of sugar structures of proteins, especially recombinant proteins. It further relates to the use of deglycosylated enzymes in the determination of sugar structures with the aid of an enzyme-substrate reaction; the invention further relates to a method of determining the sugar structures of proteins, a sugar determination kit and the use of said kit for the determination of sugar structures, especially of recombinant therapeutic proteins, preferably immunoglobulins.