Structural studies on fetal mucins from human amniotic fluid. Core typing of short-chain O-linked glycans.
Mucins in human amniotic fluid are represented by two distinct molecular species, FM-1 and FM-2, with apparent molecular masses of 700 and 570 kDa, respectively, in SDS/polyacrylamide gradient gels. FM-1 and FM-2 were isolated by preparative SDS/PAGE to apparent homogeneity and subjected to structural studies on their carbohydrate portions. The carbohydrate compositions of the mucin species differed only marginally and exhibited significant amounts of mannose. O-linked core-region glycans on human amniotic mucin-derived pronase-stable glycopeptides were analyzed after reductive beta-elimination and purification on HPLC by a combination of methylation analysis, electron-impact mass spectrometry of permethylated oligosaccharide alditols and fast-atom-bombardment mass spectrometry of acetylated or methylated alditols (positive-ion mode) or alditol-derived neoglycolipids (negative-ion TLC-MS). The primary structures of major monosaccharides to tetrasaccharides have been established which exhibit at their reducing termini core 1, core 2 and core 3 sequences, as follows. [Table; see text]
Hanisch
F G
FG
Institute of Immunobiology, University Clinic of Cologne, Federal Republic of Germany.
Peter-Katalinic
J
J
D000653:Amniotic Fluid / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis; D005260:Female; D006020:Glycopeptides / Q000737:chemistry; D006026:Glycoside Hydrolases; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009077:Mucins / Q000737:chemistry* / Q000302:isolation & purification; D009844:Oligosaccharides / Q000737:chemistry* / Q000302:isolation & purification; D011247:Pregnancy; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013402:Sugar Alcohols / Q000032:analysis
D000939:Epitopes; D006020:Glycopeptides; D009077:Mucins; D009844:Oligosaccharides; D013402:Sugar Alcohols; D006026:Glycoside Hydrolases