Quantitative glycoproteomics of HEK293 derived cell lines. Reduced N-glycosylation of acceptor sites in cell lines that lack STT3A (A) or STT3B (B). Differences in glycosylation site occupancy are expressed as Δlog₂. The blue lines are the mean Δlog₂ values from two or more LC-MS/MS experiments. Error bars are SDs (n = 3–8) or individual data points (n = 2). The number of quantified sites, proteins from which they are derived, predicted sites, and calculated coverage are shown. (C) The Δlog₂ values for selected glycoproteins with three or more quantified sites. Color-coded boxes indicate the dataset and highlight the Δlog₂ range. (D) Percentage of glycosylation sites in different protein classes with Δlog₂ < −1.