Endotoxin Binding and Neutralizing Activity by a Protein from Limulus polyphemus

摘要

Bacterial endotoxins are high molecular weight complexes associated with theouter membrane of Gram-negative bacteria. The complex is composed of lipid, carbohydrate and protein and has been characterized by an overall negative charge and heat stability. Endotoxin which has been extracted by the method of Westphal and Jann is highly purified and free of protein. This protein-free, biologically active fraction is a lipopolysaccharide (LPS) consisting of three covalently linked moieties; lipid A, core polysaccharide and O-specific polysaccharide. The molecule therefore is amphoteric, having both hydrophobic and hydrophilic domains. It is known that the lipid A moiety is responsible for biological activity, while the polysaccharide portion confers immunity.