Subject(s)
Cytosine/analogs & derivatives , Cytosine/analysis , DNA/analysis , Animals , Cattle , Chromatography, Gas , Female , Male , Mass Spectrometry , Methods , Methylation , Mice , Salmon , Spermatozoa/analysis , Thymus Gland/analysisABSTRACT
Knowledge of the structure of carcinoembryonic antigen (CEA) is essential if we are to understand the relationship of this molecule to similar, possibly cross-reacting, molecules present in nonmalignant states. Electron microscopy shows that at neutral pH, CEA particles consist of homogeneous, morphologically distinctive, twisted rod-shaped particles, about 9 X 40 nm. The carbohydrate structure of CEA has been studied by periodate oxidation. All the N-acetylneuraminic acid and fucose and a portion of the galactose and mannose were destroyed by the first periodate treatment without altering immunological activity. N-Acetylneuraminic acid was shown to be linked to galactose since its prior removal with neuraminidase led to an equivalent increased destruction of galactose by one treatment with periodate. Significantly, even after 100% of the fucose and N-acetylneuraminic acid, 75% of the galactose, and 50% of the N-acetylglucosamine and mannose were destroyed by serial periodate oxidation (Smith degradation), the remaining portion of the CEA molecule lost no more antigenic activity than did control samples where periodate was omitted. No carbohydrate was lost or destroyed in the control reaction.
Subject(s)
Carcinoembryonic Antigen , Carbohydrates/analysis , Chemical Phenomena , Chemistry , Colonic Neoplasms/immunology , Humans , Liver Neoplasms/immunology , Methylation , Monosaccharides/analysis , Oxidation-ReductionABSTRACT
The carbohydrate structural units of carcinoembryonic antigen samples isolated from four different tumors were quantitated using gas chromatography-mass spectrometery after methylation and subsequent conversion to their alditol acetates. Different carcinoembryonic antigen preparations showed some quantitative but no qualitative differences in the structural units present. The results indicate that a large portion of the fucose residues in the glycoprotein were linked to N-acetylglucosamine and that most of the branching mannose residues were probably linked to three N-acetylglucosamine residues.
Subject(s)
Carcinoembryonic Antigen/analysis , Acetylglucosamine/analysis , Carbohydrates/analysis , Chromatography, Gas , Fucose/analysis , Mass Spectrometry , MethylationABSTRACT
The structure of carcinoembryonic antigen is being determined as an approach to greater diagnostic specificity in the radioimmune assay. Examination by combined gas chromatography-mass spectrometry of derivatized saccharides from CEA has given a general outline of its carbohydrate structure. Sialic acid and fucose were completely destroyed, and galactose and mannose were partially destroyed by a single periodate treatment. Serial periodate oxidation (Smith degradation) destroyed additional amounts of galactose and mannose, as well as significant amounts of N-acetylglucosamine. Antigenic activity persisted, indicating that the residues destroyed played little, if any, part in the antigenicity of DEA.
Subject(s)
Colonic Neoplasms/immunology , Animals , Carcinoembryonic Antigen/analysis , Chemical Phenomena , Chemistry , Colonic Neoplasms/metabolism , Mass Spectrometry , Microscopy, Electron , Oxidation-Reduction , Periodic Acid/metabolismSubject(s)
Amino Acids , Dipeptides , Alanine/analogs & derivatives , Amino Acid Sequence , Fluorescamine/analogs & derivatives , Leucine/analogs & derivatives , Mass Spectrometry , Molecular Conformation , Phenylalanine/analogs & derivatives , Structure-Activity Relationship , Threonine/analogs & derivativesSubject(s)
Amino Acids , Ethylenediamines/isolation & purification , Thiazoles , Aniline Compounds , Boric Acids , Lysine , Mass Spectrometry , Methods , Phenylalanine , Serine , ThreonineABSTRACT
Structural studies on the carbohydrates of Groups A, C, and A-variant (AV) streptococci have utilized periodate oxidation, permethylation analysis, and immunochemical comparison of intact and periodate-oxidized polysaccharides. The data indicate that a similar 1,2- and 1,3-linked rhamnose chain is present in both the A and AV carbohydrates. The group A carbohydrate contains in addition N-acetylglucosamine residues at nonreducing terminals, whereas the AV is a homopolymer of rhamnose. There is some evidence that Group Ccarbohydrate contains the same rhamnose chain, but structural comparisons to the A and AV carbohydrates are complicated by the presence of intrachain N-acetylgalactosamine residues. Periodate oxidation and permethylation analysis show that while approximately 50% of the N-acetylgalactosamine of the Group C carbohydrate occupies terminal positions, the remainder is present as 1,3-linked units. Removal of the nonreducing terminal hexosamine units from the Group A carbohydrate by periodate treatment significantly enhanced its cross-reactivity with AV antiserum, whereas no enhancement was observed after similar treatment of the Group C carbohydrate. The data indicate the presence of an alpha-1,3-linked N-acetylgalactosamine disaccharide at the nonreducing terminal of the Group C carbohydrate.
