Title : Purification and characterization of the
MUC1 mucin-type
glycoprotein ,
epitectin , from human urine: structures of the major oligosaccharide alditols
Abstract :
- The MUC1 glycoprotein , epitectin , a component of the human bladder epithelium, was purified from human urine
- Sedimentation equilibrium analysis and gel filtration using polysaccharide or protein standards revealed a polydisperse preparation with molecular weights ranging from about 0.9 to 1.3 x 10(6)
- This suggests that in the native state epitectin exists as aggregates of three or four monomer units of 350-400 kDa
- Epitectin was found to have significant affinity to hexyl-, octyl- or phenyl agarose indicating that hydrophobic interactions and possibly carbohydrate-carbohydrate interactions may be responsible for the self-association
- Chemical and enzymic deglycosylation of [125I]-labeled urine epitectin and metabolically labeled H.Ep.2 epitectin resulted in extremely polydisperse products
- The buoyant densities of epitectin purified from urine and H.Ep.2 cells were found to be 1. 39-1 .40 g ml(-1 ), suggesting that the total carbohydrate content of these preparations is not significantly different
- The O-linked saccharides of epitectin were fractionated by HPLC and analyzed by permethylation and FAB-MS
- The neutral saccharides from both sources contain three common structures, namely Gal1 --> 3GalNAc, GlcNAc1 --> 6 (Gal1 --> 3) GalNAc and Gal1 --> 4GlcNAc --> 6 (Gal1 --> 3)GalNAc
- The sialic acid of urine epitectin consisted entirely of N-acetylneuraminic acid
- The two sources of epitectin , in vitro labeled on sialic acid, were found to have the same sialyl oligosaccharides but in different proportions
- Metabolic labeling and N-glycanase susceptibility experiments firmly established the presence of N-linked saccharides in epitectin as minor components
- The remarkable similarities in the total carbohydrate content, the carbohydrate composition and structures of saccharides between epitectin from urine, a non-malignant source, and H.Ep.2 cells is surprising in view of the prevailing view that MUC1 glycoproteins of cancer cells are underglycosylated compared to those produced by non-malignant cells
Output (sent_index, trigger,
protein,
sugar,
site):
- 0. glycoprotein, , epitectin, -, -
- 0. glycoprotein, , glycoprotein, -, -
- 1. glycoprotein, , MUC1 glycoprotein, -, -
- 1. glycoprotein, , epitectin, -, -
- 11. presence, , epitectin, N-linked saccharides, -
- 12. glycoproteins, , MUC1 glycoproteins, -, -
- 12. underglycosylated, , MUC1 glycoproteins, -, -
- 5. deglycosylation, , epitectin, -, -
- 7. epitectin, , epitectin, The O-linked saccharides, -
- 9. epitectin, , epitectin, The sialic acid, -
Output(Part-Of) (sent_index,
protein,
site):
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):