Fig. 1.

Overview of the experimental workflow. A, The secretome was collected as conditioned medium from cell lines in culture. HCC1143, HCC1937 and HCC2218 were also cultured under SILAC conditions to generate a super-SILAC mix as an internal standard. B, N-glycosylated peptides were enriched using N-glyco FASP. Proteins were first digested to peptides and N-glycosylated peptides were then captured using lectins. Finally, N-glycosylated peptides were released by deglycosylation using PNGase F and the deglycosylated peptides were analyzed by LC-MS.