Release of oligosaccharides from human erythrocyte membranes of different blood-group-P phenotypes by trifluoroacetolysis.

Abstract

Human erythrocyte membranes of different blood-group-P phenotypes have been degraded by trifluoroacct olysis at conditions that will effect transamidation. This degradation resulted in dissolution of the membranes with concomitant degradation of proteins. Oligosaccharide chains linked to proteins and ceramides were released as their pertrifluoroacetylated derivatives, which generally are stable towards further action of the reagent. 2-Acetamido-2-deoxy-sugar residues were converted into their corresponding 2-deoxy-2-trifluoroacetamido derivatives. The mixture of pertrifluoroacetylated oligosaccharides obtained was de-O-trifluoroacetylated and de-N-trifluoroacetylated, reduced, acetylated, permethylated and analyzed by gas-liquid chromatography/mass spectrometry. Membranes obtained from two individuals with phenotype B, p̄ (known to contain an excess of lactosyl ceramide) gave almost identical results with lactose released as the main component. From AZB, Pk1 cell membranes small amounts of lactose were obtained but the trisaccharide Gal(α1-4)Gal(β1-4)Glc was the major component found. This trisaccharide is most likely derived from the Pk antigen (trihexosyl ceramide). Membranes from a donor with the phenotype B.P1 yielded small amounts of both lactose and the Pk trisaccharide together with a larger quantity of the tetrasaccharide GalNAc(β1-3)Gal(α1-4)Gal(β1-4)Glc. The tetrasaccharide represents the carbohydrate portion of the P antigen (globoside). From all three types of membranes the B-specific trisaccharide Gal(α1-3)Gal was obtained. This compound is probably derived from specific degradation of blood-group-B-active glycoproteins and/or glycolipids. In addition to the oligo-saccharides mentioned above a large number of others were observed but in lower amounts.