Figure 2.

Comparison of GlcNAz metabolic incorporation versus the galactosyltransferase labeling after N- or O-deglycosylation. A 100 μg of proteins corresponding to whole proteins extract or to cytosol-enriched fraction were labeled with Alexa Fluor^® 488 after metabolic incorporation of Ac₄-GlcNAz (A) or enzymatic labeling with galactosyltransferase (B). After electrophoresis, blue epi-illumination was applied on gels to detect the Alexa Fluor^® 488-labeled proteins. Gels were fixed and stained with Sypro Ruby; red epi-illumination permitted the detection of the whole pattern of proteins or cytosol-enriched proteome. Proteins were deglycosylated prior to the labeling with fluorophore. (1) Corresponded to control conditions, i.e., the non-deglycosylated proteins; (2) to N-deglycosylated proteins using peptide:N-glycosidase F; (3) to chemically O-deglycosylated proteins after β-elimination; and (4) to enzymatically deglycosylated proteins by β-N-acetyl-hexosaminidase.