Lewis blood group fucolipids and their isomers from human and canine intestine.

Abstract Glycolipids containing fucose linked to N-acetylglucosamine were isolated and characterized from 14 individual human and 13 individual dog intestines. From 8 of the dog intestines, Lewis a isomer fucolipids were isolated, all identical and having the structure Gal(beta 1 leads to 4)[Fuc alpha 1 leads to 3]GlcNAc(beta 1 leads to 3)Gal(beta 1 leads to 4)Glc-ceramide. Lewis b isomer fucolipids were isolated from 12 of the intestines, all identical and having the structure Fuc(alpha 1 leads to 2)Gal(beta 1 leads to 4)[Fuc alpha 1 leads to 3]GlcNAc(beta 1 leads to 3)Gal(beta 1 leads to 4)Glc-ceramide. Lewis a-active glycolipids were isolated as the sole major fucolipid in 6 of the human intestines and differed from the canine isomer only in the position of the linkage of galactose to N-acetylglucosamine, having the beta 1 leads to 3 (type 1) rather than the beta 1 leads to 4 (type 2) linkage. Lewis b-active fucolipids were isolated from 8 human intestines and differed from their canine isomer only in that they, too, had the type 1 rather than the type 2 oligosaccharide chain. Lewis a and b glycolipid isomers commonly co-existed in canine intestine as major fucolipids whereas Lewis a and b glycolipids did not so co-exist in human intestine. In all of the fucolipids, only hydroxylated fatty acids were present and phytosphingosine and sphingosine were the predominant long chain bases. These findings are of interest in the biosynthesis of these substances and in their genetic expression.