ABSTRACT
The lipopolysaccharide (LPS) from the outer leaflet of the outer membrane of gram-negative bacteria is a highly acidic and amphipathic macromolecule. LPS. LPS is the compound responsible for the numerous pathophysiological effects expressed in gram-negative septic shock. The effects can all be attributed directly to the lipid A moiety of the LPS. This built-in asymmetry of LPS is characteristic of much simpler lipids, soaps, detergents, and cationic surfactants, which have been studied extensively. For LPS some of the most important information needed include the extent to which free molecules exists in an aqueous fluid in biological and laboratory systems along with self-aggregates such as micelles and membrane- or protein-bound molecules. Distinctions must be made between single fluid phase solutions, with or without micelles, and systems where some self-aggregates are present as one or more solid-like phases, however finely dispersed.
