Fig. 6.

Detection of alkyne-labeled glycoproteins in cell extracts. Glycoproteins labeled with alkynyl sugars were derivatized and detected by immunoblotting of biotin tag (A) or fluorescent imaging of fluorogenic coumarin probe 7 (B). Protein extracts from cells grown with different sugars were analyzed (lane 1, control Fuc 3; lane 2, alkynyl Fuc 1; lane 3, control ManNAc 5; lane 4, alkynyl ManNAc 4). The protein gel (4–12%) was subsequently stained by Coomassie blue after fluorescent imaging, to verify equal protein loading.