CHARACTERIZATION OF A HEMORRHAGIC FACTOR, LHF-I, ISOLATED FROM THE BUSHMASTER SNAKE (LACHESIS-MUTA-MUTA) VENOM

Hemorrhagic factor I (LHF-I) was previously purified from the venom of the bushmaster snake (Lachesis muta muta). In terms of biochemical an d immunological properties, LHF-I is a glycoprotein (mel. wt 100,000, pI 4.7) consisting of two subunits; it loses its activity following me rcaptoethanol treatment. LHF-I contains 0.7 g-atom zinc and 1.2 g-atom calcium per mole protein. The hemorrhagic and the proteinase activiti es are inhibited by EDTA; subsequent addition of Ca2+ or Mg2+ does not reverse the EDTA-induced inhibition of the hemorrhagic activity. The metalloenzyme does not hydrolyze arginine esters and is devoid of phos pholipase A(2) activity. It hydrolyzes the A alpha- > B beta-chain of fibrinogen without clot formation and hydrolyzes selectively the alpha -chain of fibrin, leaving the B beta-and tau-chains unaffected. Antibo dies to the hemorrhagic factor in bushmaster venom were produced by im munizing rabbits with the purified protein. The antibody was purified by protein-A affinity chromatography. This antibody was also used to s creen other Crotalinae venom samples for immunologically similar epito pes by ELISA assay. The purified antibody reacted only with LHF-I and two samples of bushmaster venom from different geographical locations.