Three forms of blood group H-glycolipid (Hi, H2, H3 variants) were isolated from lipid extract of blood group O human erythrocyte membrane. The structure of one form of H-glycolipid (Hi-glycolipid) was determined as L-fucopyranosyl-a-(l ^-2)-galactopyranosyl-(3-(l -*-4)-lV-acetylglucosaminosyl-13-(1 -»-3)-galactopyranosyl-3-(l -» 4)-glucopyranosyl-(3-(l-»-l)-ceramide, i.e., "type 2" H-chain (Painter, T. J., Watkins, W. M., and Morgan, W. T. J. (1963), Nature (London) 199, 282; Watkins, W. M. (1966), Science 152, 172) is linked to lipid. No "type 1" H chain was found as lipid bound I3lood group A, B, H, Lea, and Leb glycosphingolipids of human erythrocyte membranes have been isolated and partially characterized as having a common carbohydrate skeleton that contains fucose, glucosamine, galactose, and glucose (Yamakawa et Hakomori and Strycharz, 1968;Hakomori, 1970;Koscielak et al., 1970). Lewis-active glycolipids and their positional isomer of human adenocarcinoma have been characterized as lacto-7V-fucopentaosyl(II)ceramide (Hakomori and Jeanloz, 1970), lacto-TV-fucopentaosyl(III)ceramide (Yang and Hakomori, 1971), and lacro-V-difucohexosyl(I)ceramide (Hakomori and Andrews, 1970). Lewisactive glycolipid of human serum was partially characterized, and the uptake of Lea-and Leb-active glycolipids by erythrocytes was demonstrated (Marcus and Cass, 1969). The backbone structure of all these glycolipids was assigned as having galactosyl(/V-acetyl)glucosaminylgalactosylglucosylceramide, based on carbohydrate composition and degradation studies (Hakomori, 1970;Iseki, 1970). However, no further evidence for this structure or for positional and anomeric linkages has yet been furnished. This paper reports separation of three H-active glycolipids of type O human erythrocyte and structure of the simplest major H-active component (Hi-glycolipid).
Materials and MethodsGlycolipids and Oligosaccharides. The following glycolipids, used as references in analysis, were prepared in our laboratory: glucosylceramide from human spleen, lactosylceramide (Gal(3l~»4Glc-«-ceramide), trihexosylceramide (Galal-»4Gal|3l-»-4Glc-«-ceramide), globoside