Lipophosphonoglycan of the Plasma Membrane of Acanthamoeba castellanii

Lipophosphonoglycan, a macromolecule that accounts for about 31% of the mass of the plasma membrane of Acanthamoeba castellanii, has been purified to apparent homogeneity from whole cells. The isolated material is highly aggregated in water, partially disaggregated in water saturated with 1-butanol, and dissociated into two rapidly migrating components under conditions of electrophoresis on dodecyl sulfate-polyacrylamide gels. Approximately 60% of the mass of the isolated compound has been accounted for as follows: neutral sugars (glucose, mannose, galactose, xylose; 5:4:1:1) 26%, amino-sugars (galactosamine, glucosamine; 3:1) 3.3%, aminophosphonates (2-aminoethylphosphonate, 1-hydroxy-2-aminoethylphosphonate; 1:1) 10%, phosphate 3.2%, and fatty acids 14%. The fatty acid composition is the subject of the accompanying paper (Dearborn, D. G., and Korn, E. D. (1974) J. Biol. Chem. 249, 3342–3346).