Synthesis of galactose derivatives that render lectin-induced agglutinating ability to liposomes

Three galactose (Gal) derivatives, Gal beta 1-n-C16H33 (1), Gal beta (1-4)-Glc beta 1-n-C16H33 (2), and Gal beta 1-(CH2CH2O)3-n-C16H33 (3), were synthesized and incorporated into liposomes prepared from egg yolk lecithin. Agglutination of these liposomes with Ricinus communis agglutinin was examined by following the change of turbidity. Liposomes containing 3 were effectively agglutinated in contrast to the cases of 1 and 2, suggesting that the oxyethylene groups act as a favorable spacer to extrude Gal groups into the water. Differential scanning calorimetry showed that 3 was mixed with egg yolk lecithin at room temperature, but 1 and 2 were in the gel state, resulting in the phase separation that makes the recognition of Gal residue with Ricinus communis agglutinin difficult.