title: Glycolipid composition of human cataractous lenses. Characterization of Lewisx glycolipids.
abstract: We have studied the glycolipid composition of human cataractous lenses. Neutral and acidic lipid fractions were isolated by column chromatographies on DEAE-Sephadex and Iatrobeads. The neutral glycolipid fraction and acidic glycolipid fraction contained 0.6-0.9 micrograms of lipid-bound glucose (Glc) per mg of protein and 0.8-1.3 micrograms of lipid-bound sialic acid (NeuAc) per mg of protein, respectively. The neutral glycolipid fraction was found to contain LacCer (39.0% of total neutral glycolipids), Gb3 (16.2%), Gb4 (1.1%), nLc4 (5.0%), X (29.0%), and Y (9.2%). The acidic lipid fraction was found to contain mainly GM3 (33.1% of the total ganglioside fraction), GM1 (8.3%), LM1 (7.3%), GD1a (16.0%), and G (30.1%). The structures of neutral glycolipids X and Y and ganglioside G were elucidated by high performance thin-layer chromatography overlay method of glycolipids, gas-liquid chromatography, proton NMR spectrometry, and liquid secondary ion mass spectrometry as follows: 1) X, Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1'Cer, III3FucnLc4 (Lex); 2) Y, Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4(Fuc alpha 1- 3)GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1'Cer, V3FucIII3FucnLc6; and 3) G, NeuAc alpha 2-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3 Gal-beta 1-4Glc beta 1-1'Cer, IV3NeuAcIII3FucnLc4 (sialosyl-Le(x)). A minor neutral glycolipid Z was isolated and tentatively characterized as GlcNAc beta 1-3?Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1'Cer (GlcNAc-Le(x)), suggesting that it may be the precursor of glycolipid Y. The major long-chain base of these human cataract glycolipids was C18:0 sphingosine (sphinganine). The major fatty acids were C16:0, C24:1 and C24:0, and monounsaturated fatty acids accounted for 40-55% of the total fatty acids.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Richmond 23298.
authors.forename: T
authors.initials: T
authors.lastname: Ariga
authors.forename: R V
authors.initials: RV
authors.lastname: Tao
authors.forename: B C
authors.initials: BC
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Yamawaki
authors.forename: H
authors.initials: H
authors.lastname: Yoshino
authors.forename: N J
authors.initials: NJ
authors.lastname: Scarsdale
authors.forename: T
authors.initials: T
authors.lastname: Kasama
authors.forename: Y
authors.initials: Y
authors.lastname: Kushi
authors.forename: R K
authors.initials: RK
authors.lastname: Yu
mesh_terms: D000368:Aged; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D002386:Cataract / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D005227:Fatty Acids / Q000032:analysis; D005732:Gangliosides / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D008401:Gas Chromatography-Mass Spectrometry; D006017:Glycolipids / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D006801:Humans; D007908:Lens, Crystalline / Q000737:chemistry*; D016256:Lewis X Antigen / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D002241:Carbohydrates; D005227:Fatty Acids; D005732:Gangliosides; D006017:Glycolipids; D016256:Lewis X Antigen; D009844:Oligosaccharides