Comparative biochemistry and pharmacology of salivary gland secretions. II. Chromatographic separation of the basic proteins from some North American rattlesnake venoms

Regional differences in content of small basic peptide toxins in the venoms of Crotalus adamanteus and Crotalus horridus

1. Reverse-phase HPLC and organic solvents were used to isolate small basic peptide (SBP) toxins from the venoms of Crotalus adamanteus, C. durissus terrificus, C. horridus, C. scutulatus scutulatus, C. viridis concolor, C. viridis helleri and C. viridis viridis. 2. Acid-DEP analyses indicated a high degree of toxin purity which was obtained with a single HPLC run. 3. The combined results of HPLC, immunodiffusion and electrophoresis analyses of venoms from different geographical regions indicate that the SBP toxin content in the venoms of Crotalus adamanteus, Crotalus horridus, Crotalus scutulatus and Crotalus viridis viridis may vary regionally.

Potentiation of the toxicity of basic peptides from rattlesnake venoms by sodium acetate

The potentiating effect of sodium acetate on the toxicity of crotamine from Crotalus durissus terrificus venom, E toxin from Crotalus horridus horridus venom, and myotoxin a from Crotalus viridus viridis venom was examined. Subcutaneous injection of 6.3 mg/kg body weight of either crotamine or E toxin in 0.6 ml of water or myotoxin a in 0.6 ml of 0.05 M Tris/0.1 M NaCl buffer, pH 9.0, failed to produce lethality in mice. Injection of either E toxin or crotamine at doses of 4.0 mg/kg in 0.6 ml of 20 mM phosphate, pH 7.2, containing 1 M sodium chloride also failed to produce lethality. However, when any of the toxins were injected in 0.4 ml of 1 M sodium acetate, pH 7.0, lethality was observed. LD50 values of 1.43 mg/kg for E toxin, 1.39 mg/kg for crotamine and 0.56 mg/kg for myotoxin a were determined under these conditions. Lethality was also observed when either sodium propionate or sodium butyrate was used as a carrier for E toxin. The effect of these two buffers on crotamine and myotoxin a was not examined. Injection of E toxin s.c. in water followed at various time intervals with i.p. injections of 1 M sodium acetate produced lethality, even when the acetate was injected up to 4 hr after the toxin challenge.

Ability of polyvalent (Crotalidae) antivenin to neutralize myonecrosis, hemorrhage and lethality induced by timber rattlesnake (Crotalus horridus horridus) venom

The local and lethal effects of crude Crotalus horridus horridus venom were quantitated and the ability of polyvalent (Crotalidae) antivenin to neutralize these effects was studied. A light microscopy assay was used to measure myonecrosis, a new method based on the amount of hemoglobin present in the injected muscle was used to measure hemorrhage and the LD50 was used as a measure of lethality. Results indicate that polyvalent (Crotalidae) antivenin significantly neutralized myonecrosis in mice at venom doses of 3.0 and 6.0 micrograms/g, hemorrhage at doses of venom up to 12.0 micrograms/g, and lethality at a dose equivalent to 2.5 times the LD50.

Isolation and characterization of a hemorrhagic proteinase from timber rattlesnake venom

A protein isolated from timber rattlesnake (Crotalus horridus horridus) venom by ion-exchange and high-pressure liquid chromatography is hemorrhage inducing and lethal to mice (LD50 of 10 micrograms/g of body weight). It is a Ca2+- and Zn2+-containing proteinase and has the ability to hydrolyze hide powder azure. Atomic absorption spectroscopy shows 2.5 Ca2+ and 1 Zn2+ per protein monomer. The proteinase activity is destroyed by incubation with disulfide-reducing agents and by dialysis against ethylenediaminetetraacetate. Coincident with the loss of proteinase activity is a corresponding loss of lethal and hemorrhagic activities, suggesting that all three are related. Attempts to replace the metals and restore activity have been unsuccessful. Amino acid analysis and isoelectric focusing reveal that this component is an acidic protein (pI = 5.1) containing about 20 disulfide bonds and 507 residues. Reduction of one disulfide bond per molecule decreases proteinase activity by 50% while reduction of eight disulfide bonds decreases activity by 80%. Loss of hemorrhagic activity parallels the decrease in proteinase activity.

Local necrotizing effect of snake venoms on skin and muscle: relationship to serum creatine kinase

Twenty-five snake venoms were tested for their ability to induce an increase of serum creatine kinase (CK) level after i.m. injection (0.125-1.0 mg/kg) into rates. Of six Australian elapid venoms only those from Pseudechis colletti guttatus and P. australis produced a steep rise of CK-activity (30-70 times the normal value) 4 and 16 hr after injection (0.5 mg/kg). Viperid and crotalid venoms had only slight effects (2-5 times the normal value) even in doses of 1.0 mg/kg except for a sample of Crotalus adamanteus venom which caused a 20 fold increase in CK-level. From this venom a toxin of 5800 mol. wt. consisting of 50 amino acid residues was isolated. This toxin exhibited similarities in amino acid composition and in lethality to crotamine from Crotalus durissus terrificus and to a toxin from C. horridus horridus. The toxin from C. adamanteus induced some increase of CK-level in rats, but this does not account entirely for the activity of the crude venom, whereas crotamine and the toxin from C. horridus horridus were ineffective. Phospholipase A2 (fraction II) from Pseudechis colletti guttatus venom caused a dose-dependent increase of CK-level and myoglobinuria. Intradermal injection of snake venoms into mice is useful for testing hemorrhagic activity, but is too insensitive to measure necrotizing effects. Venom induced myonecrosis can be evaluated by assaying the CK-serum level and by histological examination.

Isolation, stabilization, and characterization of a toxin from timber rattlesnake venom

A rapid and convenient method for the purification of a toxin from timber rattlesnake, Crotalus horridus horridus, venom using carboxymethyl cellulose ion-exchange chromatography has been devised. The toxicity of this venom component is labile, but it is stabilized by the addition of 20+ V/V glycerol to the buffer solution. This toxin has a molecular weight of 15,000 +/- 700 as determined by SDS gel electrophoresis. It is both heat and protease resistant. Treatment of this venom component with 2-mercaptoethanol followed by G-50 Sephadex chromatography causes no loss of toxicity although incubation of the toxin with 1% SDS and 1% 2-mercaptoethanol prior to electrophoresis does result in a faster migrating species. The toxin does not affect neuromuscular junctions but does appear to act on the nervous system. It causes no local responses in mice.

Comparative biochemistry and pharmacology of salivary gland secretions. III. Chromatographic isolation of a myocardial depressor protein (MDP) from the venom of Crotalus atrox

A protein has been isolated from the venom of the western diamondback rattlesnake (Crotalus atrox) which induces acute myocardial depression when administered to experimental animals. Purification was achieved by gel filtration on Sephadex G-100, DEAE- and CM-cellulose ion-exchange chromatography, ultra-filtration, and adsorption chromatography on hydroxyapatite. Amino acid analysis of the highly purified protein indicated N-terminal isoleucine and C-terminal tyrosine residues, and the absence of free sulfhydryl groups. Rabbits were immunized against the myocardial depressor protein (MDP) and a highly specific antiserum prepared which made it possible to study other snake venoms for the presence or absence of MDP. All of the North American Crotalid species of snakes contain MDP in varying degrees of concentration, but none of the Asiatic snake venoms tested reacted with the antiserum to the myocardial depressor protein. Intravenous administration of MDP to experimental animals (dogs, cats) produces an immediate and profound decrease in the cardiac output, the left ventricular systolic and mean pressures, the velocity of shortening of the contractile element, the systemic arterial pressure and an elevation in the left ventricular end-diastolic and pulmonary wedge pressures. These hemodynamic changes indicate that MDP administration induces an acute myocardial failure which is does dependent. The potential use of this protein for the reproducible causation of left ventricular failure, obviating the need for the more commonly used surgical ligation of the coronary arteries, warrants a full investigation into its structure, active site and its mechanism of action on the myocardial cell.

Studies of an acidic cardiotoxin isolated from the venom of Mojave rattlesnake (Crotalus scutulatus)

A major lethal protein was isolated from the venom of Mojave rattlesnake (Crotalus scutulatus) by successive purification in DEAE column chromatography and isoelectric focusing. This homogeneous and monomeric form of toxin is designated as "Mojave toxin". Unlike basic neurotoxins or cytotoxins isolated from venoms of cobras, kraits and sea snakes, the Mojave toxin is an acidic protein with an isoelectric point of 4.7. The toxin is also different from crotoxin (from Crotalus durissus terrificus) which consists of both acidic and basic components. The molecular weight determined by Sephadex G-75 column chromatography resulted in a value of about 22 000. A singel protein band with a molecular weight of about 12 000, was observed after sodium dodecyl sulfate gel electrophoresis of the reduced Mojave toxin. Isoelectric focusing gel in the presence of 8 M urea also showed a single protein band, suggesting that the toxin is composed of subunits. Unlike the neurotoxic nature of the basic proteins from the venoms of Elapidae and sea snakes (Hydrophiidae) and crotoxin, Mojave toxin is cardiotoxic rather than neurotoxic. It is very likely that venoms of all rattlesnakes from North and Central America contain Mojave toxin as the common toxin.