title: Chromogenic substrates for horseshoe crab clotting enzyme. Its application for the assay of bacterial endotoxins.
abstract: An endotoxin-activated hemocyte lysate from the horseshoe crab (Tachypleus and Limulus) was found to hydrolyze Bz-Ile-Glu-(gamma-OR)-Gly-Arg-p-nitroanilide (PNA), Bz-Val-Gly-Arg-PNA, Boc-Val-Leu-Gly-Arg-PNA, and Boc-Leu-Gly-Arg-PNA, all of which have the COOH-terminal Gly-Arg sequence. This amidase activity was due to a clottting enzyme contained in the lysate. Furthermore, the amidase activity increased by increasing the concentration of bacterial endotoxin (E. coli, 0111-B4) added to the lysate. Therefore, the measurement of the endotoxin-induced amidase activity made it possible to determine the concentration of the endotoxin.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000991:Antithrombins; D001777:Blood Coagulation; D004731:Endotoxins; D006737:Horseshoe Crabs / Q000201:enzymology*; D009842:Oligopeptides; D010455:Peptides; D014568:Urokinase-Type Plasminogen Activator
chemical_list: D000991:Antithrombins; D004731:Endotoxins; D009842:Oligopeptides; D010455:Peptides; D014568:Urokinase-Type Plasminogen Activator