Characterization of B and H blood-group active glycosphingolopids from human B erythrocyte membranes

Abstract

Two blood group B active glycosphingolipids (B-I and B-II) previously isolated and highly purified from human B erythrocytes [21] were analysed first by degradation with alpha-D-galactosidase from coffee beans, alpha-L-fucosidase from bovine kidney and with 0,1 N trichloracetic acid; the native B-glycolipids as well as their degradation products were then investigated by methylation analysis with combined gas chromatography-mass spectromety, by thin layer chromatography, two dimensional immunodiffusion and by the hemagglutination inhibition technique. Together with the results obtained by mass spectrometry of permethylated glycolipids [26] the following structures were elucidated: alpha-D-gakactpurampsu;-(1 leads to 3) [alpha-L-fucopyranosyl-(1 leads to 2)]-D-galactopyranosyl-(1 leads to 4)-N-acetyl-D-glucosaminosyl-(1 leads to 3)-D-galactopyranosyl-(1 leads to 4)-D-glucopyranosyl-(1 leads to 1)-ceramide for the B-I glycosphingolipid and alpha-D-galactopyransosyl-(1 leads to 3)-[alpha-L-fucopyranosyl-(1 leads to 2)]-D-galactopyranosyl-(1 leads to 4)-N-acetyl-D-glucosaminosyl-(1 leads to 3)-D-galactopyranosyl-(1 leads to 4)-N-acetyl-D-glucosaminosyl-(1 leads to 3)-D-galactopyranosyl-(1 leads to 4)-D-glucopyranosyl-(1 leads to 1)-ceramide for the B-II glycophingolipid. AH active glycolipid fraction from B erythrocytes further purified by thin layer chromatography was also investigated by methylation analysis. The pattern of its partially methylated alditol acetates was essentially the same as that of the alpha-galactosidase treated and permethylated B-I glycoliped. It is also exhibited strongly precipitating and hemagglutination inhibiting H properties as well as the two alpha-galactosidase treated B-I and B-II glycosphingolipids. Based upon these data the following tentative structure was proposed: alpha-L-fucopyranosyl-(1 leads to 2)-D-galactopyranosyl-(1 leads to 4)-N-acetyl-D-glucosaminosyl-(1 leads to 3)-D-Galactopyranosyl-(1 leads to 4)-D-glucopyranosyl-( 1 leads to 1)-ceramide. Gas chromatographic analysis revealed sphingosine and lignoceric, nervonic and behenic acids to be the main components of the ceramide residues of the three glycophingolipids. From the data presented the H active substance very probably can be regarded as the immediate precursor of the B-I gly cosphingolipid from human B erythrocyte membranes.