title: Isolation and biological activities of limulus anticoagulant (anti-LPS factor) which interacts with lipopolysaccharide (LPS).
abstract: Exposure of limulus hemocytes to bacterial endotoxins (lipopolysaccharide, LPS) results in the activation of the intracellular clotting system, consisting of several protein components. During the separation of these components, a potent anticoagulant, named anti-LPS factor, which inhibits the endotoxin-mediated activation of the coagulation cascade, was found in hemocytes from both Tachypleus tridentatus and Limulus polyphemus (Tanaka, S., et al. (1982) Biochem. Biophys. Res. Commun. 105, 717-723). The principle isolated from the Tachypleus hemocyte lysate by column chromatographies on dextran sulfate-Sepharose CL-6B and Sephadex G-50 under sterile conditions was a simple basic protein with an apparent molecular weight of 15,000. It consisted of a single chain polypeptide containing a total of 128 amino acids. The COOH-terminal end was presumed to be histidine, but no NH2-terminal end reactive to phenylisothiocyanate was detected. The isolated anti-LPS factor specifically inhibited the endotoxin-mediated activation of factor C, which has recently been identified as an LPS-sensitive serine protease zymogen in the hemocytes. This inhibition appeared to be due to the binding of anti-LPS factor with LPS. Moreover, anti-LPS factor had an antibacterial effect on the growth of Gram-negative bacteria (Salmonella minnesota R595 and 1114W) but not on that of Gram-positive bacteria (Staphylococcus aureus 209P). These biological activities of the isolated anti-LPS factor suggest an important role in cellular defence of limulus against microbial invasion.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000900:Anti-Bacterial Agents; D000925:Anticoagulants / Q000302:isolation & purification*; D023181:Antimicrobial Cationic Peptides; D060829:Arthropod Proteins; D001419:Bacteria / Q000187:drug effects; D001780:Blood Coagulation Tests; D002850:Chromatography, Gel; D006737:Horseshoe Crabs / Q000032:analysis*; D007447:Invertebrate Hormones / Q000302:isolation & purification* / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D011506:Proteins / Q000032:analysis
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D000925:Anticoagulants; D023181:Antimicrobial Cationic Peptides; D060829:Arthropod Proteins; D007447:Invertebrate Hormones; D011506:Proteins; C034705:antilipopolysaccharide factor (Limulus)