Fig. 3. Gel results of metabolic labeling and click chemistry. (a) Protein staining signals demonstrated that protein bands were the same in the different lanes for the control sample from unlabeled cells, the lysate sample (labeled cells were lysed first, followed by the click chemistry reaction), and the surface sample (sialoglycoproteins on the cell surface were tagged first, then we lysed cells and extracted proteins) (b) fluorescence signals from each lane were dramatically different.