The role of cell envelope phospholipid in the enzymatic synthesis of bacterial lipopolysaccharide. Structural requirements of the phospholipid molecule.

The role of phospholipid in the uridine diphosphate-galactose :lipopolysaccharide galactosyltransferase reaction has been studied in extracts of Salmonella typhimurium by utilizing synthetic and natural phospholipids and phospholipids altered by venom digestion, alkaline hydrolysis, and catalytic hydrogenation. Activity was seen with derivatives of phosphatidic acid containing two unsaturated or cyclopropane fatty acids, and either a hydroxyl group, ethanolamine, glycerol, or polyglycerol phosphate (in cardiolipin) as the component attached to the a-phosphate group. No activity was seen with phosphatidylcholine.