Neuraminidase is an important deglycosylation enzyme capable of cleaving all non-reducing unbranched N-acetylneuraminic and N-glycolylneuraminic acid residues by hydrolysis of α(2→6), α(2→3), α(2→8), and α(2→9) linkages (affinity in the order given). Branched sialic acids may also be cleaved with the use of high concentrations of enzyme and prolonged incubations. Desialylated glycoproteins may then be further characterized by treatment with various exoglycosidases resulting in partial or complete O-deglycosylation. SDS-PAGE and MALDI-TOF MS are typically utilized in purification, structural analysis, and sequencing process. These techniques also remove heterogeneity and charge from the glycoprotein.