Studies on snake venoms. XIX. Purification and some physicochemical properties of proteinases a and c from the venom of Agkistrodon halys blomhoffii

A pharmacological and biochemical investigation of the venom from the platypus (Ornithorhynchus anatinus)

In this study several activities of the venom of Ornithorhynchus anatinus have been investigated. Whole venom induced local oedema after subplantar injection and produced relaxation of the rat uterus in vitro. The relaxant activity was partially purified by gel permeation HPLC and subsequent analyses by SDS-PAGE revealed that this activity was associated with a 4200 mol. wt peptide. The N-terminal partial sequence of this peptide exhibited substantial identity with human and porcine C-type natriuretic peptide (CNP). Three other major proteins isolated from the venom had mol. wts of 140,000, 55,000 and 16,000. None was found to have any sequence homology with proteins listed in the SwissProt database. The 140,000 mol. wt protein exhibited hyaluronidase activity but the nature of the 55,000 and 16,000 mol. wt proteins remains to be determined. Platypus venom also exhibits protease activity, although the concentration of proteolytic enzymes was too low to be visualised by SDS-PAGE using Coomassie staining.

Purification and characterization of two high molecular weight hemorrhagic toxins from Crotalus viridis viridis venom using monoclonal antibodies

Two high mol. wt hemorrhagic toxins were purified from Crotalus viridis viridis venom using HPLC anion exchange and monoclonal antibody affinity chromatography following initial separation by HPLC with a preparative DEAE column. The fraction from the initial column having the highest hemorrhagic activity was used to immunize BALB/c mice for production of monoclonal antibodies. One of the monoclonal antibodies specifically recognized a single protein band of the immunizing fraction in native polyacrylamide gel electrophoresis. This monoclonal antibody was purified and conjugated to activated membranes for affinity purification of the antigen from the hemorrhagic fraction. Proteins eluted from the affinity membranes showed three bands in SDS-PAGE with apparent mol. wts of 68,000, 62,000 and 30,000. The 68,000 and 62,000 mol. wt proteins were further purified using an analytical DEAE column, and purity was demonstrated by the presence of a single band in SDS-PAGE and a single precipitation arc against antibodies to Crotalus viridis viridis venom in immunoelectrophoresis. The 68,000 (pI of 8.5) and 62,000 (pI of 4.1) proteins are highly hemorrhagic metalloproteinases which cleave N,N-dimethylcasein and fibrinogen. Both are glycoproteins with the same galactose-beta (1-4)-N-acetylglucosamine side-chains linked to asparagine residues. Treatment of both toxins with glycosidase F blocked their hemorrhagic activities. Oxidation of the sugar moieties by periodate inhibited the hemorrhagic activity of the 62,000 toxin, but not of the 68,000 mol. wt toxin.

Structural domains in venom proteins: evidence that metalloproteinases and nonenzymatic platelet aggregation inhibitors (disintegrins) from snake venoms are derived by proteolysis from a common precursor

A comparison of the structures of a precursor of trigramin (a disintegrin), metalloproteinases, disintegrins and related proteins, suggests the existence of common precursors for metalloproteinases and disintegrins. The proposed common precursor and related proteins have four distinct domains (A-D). Domain B contains the metal binding site and the catalytic Glu residue, which comprise the active site of metalloproteinases. Domain C contains the Arg-Gly-Asp sequence and hence the ability to inhibit the activity of integrins. Domains A and D are unique and their biochemical or biological activity is unknown. The proposed precursor can be proteolytically cleaved at several interdomain sites, releasing the disintegrins and metalloproteinases. A survey of more than 100 venom metalloproteinases and disintegrins strongly supports the existence of precursor proteins and their structural domains. This is also upheld by the co-occurrence occurrence of metalloproteinases and disintegrins in the venoms of several genera of crotalid and viperid snakes. The likelihood of intradomain disulfide bridges, and accessibility of all interdomain cleavage sites also supports our contention. The susceptibility of the cleavage sites appears to be determined by nearby disulfide bridges and glycosylation. Recognition of the proposed structural domains of venom proteinases should help clarify the structure-function relationships of several related proteins, and influence the synthesis of recombinant disintegrins, metalloproteinases and related polypeptides.

Pathogenesis of hemorrhage induced by bilitoxin, a hemorrhagic toxin isolated from the venom of the common cantil (Agkistrodon bilineatus bilineatus)

The pathogenesis of hemorrhage induced by the i.m. injection of the hemorrhagic toxin, bilitoxin, was studied using light and electron microscopy. White mice were injected with sublethal doses of the toxin, and tissue samples were obtained at 5 and 30 min, and 1, 3 and 24 hr after the injection. There was a good correlation between amount of toxin injected and amount of hemorrhage observed. Microscopically, hemorrhage was visible in all parts of the connective tissue surrounding muscle cells just 5 min after injection and fibrin was present both intravascularly and extravascularly. At later time periods the hemorrhage was more extensive and there was more fibrin. Many vessels were plugged with platelets. At 30 min after the injection, muscle cells appeared to be damaged having either delta lesions or disrupted myofibrils. Electron microscopy revealed damaged capillaries with ruptured endothelial cells, disrupted basal lamina and intact intercellular junctions. Thus, this hemorrhagic toxin acts rapidly to disrupt the capillary endothelium without damaging the intercellular junctions, and it also appears to damage skeletal muscle cells.

Biophysical properties and amino acid composition of Bothrops protease A, a proteolytic enzyme isolated from the venom of the snake Bothrops jararaca (jararaca)

Bothrops protease A, an arginine-ester hydrolase, is active on protamine, gelatin and insulin and was isolated from the venom of Bothrops jararaca in a homogeneous state, as judged by polyacrylamide gel electrophoresis and ultracentrifugal analyses. The enzyme has a molecular weight of 65,000 and a pI of 3.55. The enzyme is a glycoprotein whose amino acid content corresponds to 55% of the molecular weight.

Isolation and characterization of a proteolytic enzyme from the venom of the snake Bothrops jararaca (Jararaca)

Bothropasin, one of the proteases from the venom of Bothrops jararaca active on casein, was isolated by ammonium sulfate precipitation, DEAE-cellulose and DEAE-Sephadex A-50 chromatographies and Sephadex G-100 column filtration. The preparation possessed no other detectable activities which are present in the crude venom. Addition of Ca2+ during purification stabilized the enzyme. The endopeptidase was inhibited by EDTA and EGTA; Ca2+ did not restore the activity of the inhibited enzyme. The material was homogeneous by polyacrylamide gel electrophoreses at different pH values, immunoprecipitation and crossed immunoelectrophoresis. By SDS-polyacrylamide gel electrophoresis the denatured and reduced enzyme had only a 48,000 molecular weight band. In the presence of 6 M guanidine-HCl and 0.1 M beta-mercaptoethanol the preparation showed a value of 49,870 by sedimentation equilibrium. The native tertiary structure of the protein is dependent on S-S and metal bonds. The denatured and reduced enzyme, in the presence of EDTA, showed a molecular weight of 37,300 by sedimentation equilibrium, a value which was also confirmed in SDS-polyacrylamide gel electrophoresis. The enzyme hydrolyzed five peptide bonds: His-Leu (5-6), His-Leu(10-11), Ala-Leu(14-15), Tyr-Leu(16-17) and Phe-Phe(24-25) in the B-chain of oxidized insulin.