摘要 : We previously reported the precise structure of acidic free-glycans in human urine. In the present study, structural analysis of neutral free-glycans in urine was performed in fine detail. Urine samples were collected from 21 heal... 展开 We previously reported the precise structure of acidic free-glycans in human urine. In the present study, structural analysis of neutral free-glycans in urine was performed in fine detail. Urine samples were collected from 21 healthy volunteers and free-glycans extracted from the creatinine-adjusted urine and then fluorescently labeled with 2-aminopyridine. Neutral glycan profiling was achieved by a combination of high-performance liquid chromatography, mass spectrometry, enzymatic digestion, and periodate cleavage. A total of 79 glycans were identified. Because the ABO-blood group antigen containing urinary neutral glycans are major components, profiling patterns were similar between individuals of the same ABO-group. The neutral glycans were composed of lactose-core (Gal beta 1-4Glc) glycans, type-II N-acetyllactosamine-core (GlcNAc beta 1-4Glc) glycans, hexose oligomers, N-glycans and to our surprise beta 1-3 galactosylglucose-core (Gal beta 1-3Glc) glycans. Although glycans with a beta 1-3 galactosylglucose-core were identified as major components in urine, comprising structurally simple isomers of a lactose-core, the core structure has not previously been reported. The major beta 1-3 galactosylglucosecore glycans were Fuc alpha 1-2Gal beta 1-3(Fuc alpha 1-4)Glc, GalNAc alpha 1-3(Fuc alpha 1-2)Gal beta 1-3(Fuc alpha 1-4)Glc and Gal alpha 1-3 (Fuc alpha 1-2)Gal beta 1-3(Fuc alpha 1-4)Glc, corresponding to H-, A-, and B-blood group antigens, respectively. Three lactosamine extended beta 1-3 galactosylglucose-core glycans were also detected as minor components. Elucidating the biosynthesis of beta 1-3 galactosylglucose will be crucial for understanding the in vivo function of these glycans. 收起