Engineered GalNAc-T glycosyltransferases were used to incorporate a chemically modified GalNAC analog into the secretome of HepG2 cells. The chemical modification included a bioorthogonal alkyne tag that allowed for introduction of a clickable, acid-cleavable biotin-picolyl-azide. Glycoproteins were enriched using Streptavidin, and on-bead digestion yielded solid phase-bound glycopeptides that were released with acid. Glycopeptides were analysed.