Trifluoroacetolysis, a New Method for Structural Studies of Glycolipids
Trifluoroacetolysis is a reaction which is carried out in mixtures of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) in various proportions and at different temperatures. 2-Acetamido-2-deoxy functions in sugar units are converted into 2-deoxy-2-trifluoroacetamido groups, by trifluoroacetolysis, employing TFA/TFAA in proportions varying from 1:1 to 1:50 at 100°C for 48 h (1). Under these conditions of trifluoroacetolysis most reducing sugars (2) and glycosides (3) are stable due to the stabilizing effects excerted by the O-trifluoroacetyl groups rapidly formed by the action of TFA/TFAA on the hydroxyl groups in the sugar residues. Peptide bonds are cleaved by transamidation and thus proteins and the protein part of glycoproteins will be degraded, by trifluoroacetolysis, whereas the carbohydrate portion of glycoproteins remains virtually intact, apart from some degradation of 2-acetamido-2-deoxy sugars situated at the reducing end (2,4,5). N-Glycosidically linked carbohydrate chains are cleaved off from glycoproteins by transamidation (4,5) and O-glycosidically linked carbohydrate chains are cleaved off from serine or threonine residues by an acid catalyzed elimination reaction (5,6).
KeywordsBlood Group Glycosidic Bond Sugar Residue Aqueous Acetic Acid Protein Part
Unable to display preview. Download preview PDF.
- 3.B. Nilsson and S. Svensson, Studies of the reactivity of methyl glycosides, oligosaccharides, and polysaccharides towards trifluoroacetolysis, Carbohyd. Res. in press.Google Scholar
- 4.B. Nilsson and S. Svensson, A new method for degradation of the protein part of glycoproteins. Isolation of the carbohydrate chains of asialofetuin, Carbohyd. Res. in press.Google Scholar
- 5.B. Nilsson, N.E. Nordén, and S. Svensson, Structural studies on the carbohydrate portion of fetuin, J. Biol. Chem. in press.Google Scholar
- 6.B. Lindberg, B. Nilsson, T. Norberg, and S. Svensson, Specific cleavage of O-glycosidic bonds to L-serine and L-threonine by trifluoroacetolysis, Acta Chem. Scand. Ser B in press.Google Scholar
- 7.L.-E. Fra én and S. Svensson, The stability of partially methylated methyl a-D-glucopyranosides towards trifluoroacetolysis, Carbohyd. Res. in press.Google Scholar
- 8.L.-E. Franzén and S. Svensson, The stability of partially methylated methyl a-D-xylopyranosides and partially methylated D-xyloses towards trifluoro-acetolysis, Carbohyd. Res. submitted.Google Scholar
- 9.J. Lundsten, S. Svensson, and L. Svennerholm, A method for specific cleavage of the glycosidic bond to the ceramide portion of glycolipids, FEBS Lett. in press.Google Scholar
- 10.J. Lundsten, S. Svensson, and P.A. Öckerman, GC/MS screening of urinary oligosaccharides, in: ‘Proc. Mass Spectrometry and Combined Techniques in Medicine, Clinical Chemistry and Clinical Biochemistry, Tubingen (1977), p. 193.Google Scholar
- 11.M.A. Chester and S. Svensson, unpublished results.Google Scholar
- 12.K.O. Lloyd, E.A. Kabat, and E. Licerio, Immunochemical studies on blood groups. XXXVIII. Structures and activities of oligosaccharides produced by alkaline degradation of blood-group Lewisa substance. Proposed structure of the carbohydrateb chains of human blood-group A, B, H, Lea, and Le substances, Biochemistry 7: 2976 (1968).PubMedCrossRefGoogle Scholar
- 13.A. Lundblad, S. Svensson, B. Löw, L. Messeter, B. Cedergren, and H.R. Nevanlinna, Release of oligosaccharides from human erythrocyte membranes of different blood group P phenotypes by trifluoroacetolysis, J. Biol. Chem. submitted.Google Scholar