Isolation and structures of the third major type of carbohydrate units in polysialoglycoproteins from rainbow trout eggs.

The structures of the third major type of oligosialyloligosaccharides obtained by alkali-borohydride treatment of polysialoglycoproteins of the unfertilized eggs of rainbow trout have been determined to be: alpha-L-fucosyl-(1----3)-beta-N-acetyl-D-galactosaminyl-(1----3)-beta-D- galactosyl-(1----4)-beta-D-galactosyl-(1----3)-[[(----8)-alpha-N- glycolylneuraminyl-(2----)]n-(----6)]-N-acetyl-D-galactosaminitol with n = 1 to 4. The proportion of the fucose-containing units in 3 major carbohydrate units present in fish egg polysialoglycoproteins was found to be highly species-specific and only 6% in the eggs of rainbow trout.