SnRg produced in COS-7 cells is sialylated. SnRg was precipitated with protein A-sepharose (PAS) beads and subjected to mock (lane 2), NANaseI (lane 1), Vibrio Cholerae sialidase (lane 4),Arthrobacter Ureafaciens sialidase (lane 5) digestions, or mild periodate oxidation (lane 3). Treated and nontreated SnRg (10 mg/lane) were subjected to 7% SDS-PAGE and protein detected by silver nitrate staining. Molecular mass markers (in kD) are shown.