MALDI/TOF-MS profiles of O-glycans from CHO cells transfected with PSGL1, Core2GlcNAcT, FucTVII cDNAs with or without CMP-NeuAc hydroxylase cDNA. Shown are comparisons of MALDI-MS profiles of O-glycans from CHO cells transfected with cDNA-encoding PSGL-1, Core2GlcNAcT, FucT-VII with (b) or without (a) CMP-NeuAc hydroxylase. Major peaks representing core 1 and core 2 O-glycans are annotated with structures in symbol form. Both cell populations exhibit a predominance of core 2 sialylated structures, and some O-glycans are additionally fucosylated. Transfection with CMP-NeuAc hydroxylase results in exclusive expression of N-glycolyl neuraminic acid (b), whereas cells lacking this enzyme only express N-acetyl neuraminic acid (a). N-acetylneuraminic acid (NeuAc), N-glycolylneuraminic acid (NeuGc), galactose (Gal), N-acetylglucosamine (GlcNAc), N-acetylgalactosamine (GalNAc), fucose (Fuc)