after neuraminidase treatment , the o-linked carbohydrate is susceptible to digestion with an endoglycosidase ( endo-beta-n-acetylgalactosaminidase ) that cleaves glycans with the structure gal ( beta 1 -- -- 3 ) -galnac-ser/thr , and sialic acid can be added back to this core oligosaccharide by specific sialyltransferases .
C0032594
glycans
C0028959
oligosaccharide