N-3554S, an optically active S-isomer of alpha-dihydrodecaprenyl phosphate, reduced the tumorigenicity of cultured B16-F10 mouse melanoma cells probably by affecting protein N-glycosylation. Accordingly, membrane glycoprotein samples were prepared from the melanoma cells cultured with or without N-3554S, and amounts and structures of N-linked sugar chains were determined. Analyses of the N-linked oligosaccharides released by hydrazinolysis from these samples and reduced with NaB3H4 revealed that the N-3554S-treated cells contain 1.5-1.8 times as much oligosaccharides as the control cells, and the relative amounts of high-mannose-type and bi-, tri- and tetra-antennary complex-type sugar chains are almost the same between two samples. Western blot analysis, however, showed that binding of L-PHA, which binds to oligosaccharides with the GlcNAc beta 1-->6(GlcNAc beta 1-->2)Man structure, is significantly reduced in 90 K, 96 K, 140 K, 155 K and 180 K glycoproteins in N-3554S-treated cells. Immunoblot analysis showed that the 140 K glycoprotein could be a fibronectin receptor. It was also shown that N-3554S treatment enhances the adhesiveness of the cells to fibronectin. These results indicate that N-3554S affects N-glycosylation of membrane glycoproteins and alters the cell surface properties of B16-F10 cells.