Primary structures and Lewis blood-group-dependent expression of major sialylated saccharides from mucus glycoproteins of human seminal plasma.

The primary structures of four major sialylated saccharide alditols derived from mucus glycoproteins of human seminal plasma were established by fast-atom-bombardment mass spectrometry and methylation analysis. Anomeric configurations of the glycosidic bonds were determined by exoglycosidase digestion and CrO3 oxidation. (Formula: see text) Two minor components represent isomers of the major saccharide in A6, which are probably characterized by terminal sequences NeuAc(2----3)Gal(1----4)[Fuc(1----3)]GlcNAc(1---- and Fuc(1----2)Gal(1----4)[NeuAc(2----6)]GlcNAc(1----, respectively. Based on quantitative data from high-pressure liquid chromatography and on structural information, the biosynthetic pathways for neutral and sialylated saccharides related to the Lewis system were proposed. Expression of saccharides A6, A7 and A8 and their asialo counterparts, which are characterized by antigenic determinants H, Lex and Ley, respectively, is qualitatively and quantitatively dependent on the Lewis blood type of the respective donor and correlates with Ca 19-9 activity of its seminal plasma.