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At least 19 recordsLinked to original sources
PubMed1975

A heat stable paraoxonase (O,O-diethyl O-p-nitrophenyl phosphate O-p-nitrophenyl hydrolase) from Russell's viper venom.

Fractionation of Russell's viper venom revealed separate phosphohydrolase activities directed against p-nitrophenyl phosphate, bis(p-nitrophenyl) phosphate, p-nitrophenylthymidylic acid, and O,O-diethyl p-nitrophenyl phosphate (paraoxon). On gel fractionation, the first two activities are eluted ahead of the latter. They could be resolved further by phosphocellulose cation exchange chromatography. The hydrolytic activities directed against p-nitrophenylthymidylic acid hydrolyzing component is heat labile, while the paraoxon hydrolyzing component manifests an unusually high degree of heat stability. Gel filtration yields 9600 for the molecular weight of the "paraoxonase". This enzyme, as all known enzymes of this type, requires the presence of a divalent cation. Maximum activity is obtained in the presence of Ca2+. In the presence of Sr2+ the reaction rate is 50% of that of Ca2+; other divalent cations show lower activities. The presence of the enzyme is species specific. Of four species tested, only Russell's viper venom showed significant paraoxonase activity. Enzyme activity is intact following incubation with iodoacetate of p-chloromercuribenzoate. Activity is partially preserved even in the presence of 8 M urea.

4-Nitrophenylphosphatase↗
PubMed1979

Molecular properties of the Factor V-activating enzyme from Russell's viper venom.

The protease from Russell's viper venom that activates Factor V was purified by gel filtration on Sephadex G-150 and ion exchange column chromatography on sulfopropyl (SP)-Sephadex C-50. The purified enzyme is a glycoprotein containing 6% carbohydrate. It migrated as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular weight of 29,000. A minimum molecular weight of 27,200 was determined by sedimentation equilibrium in the presence of 6 M guanidine hydrochloride. The enzyme is composed of a single polypeptide chain possessing an NH2-terminal sequence of Val-Val-Gly-Gly-Asp-Glu-Cys-Asn-Ile-Asn-Glu-His-Pro-Ile. The specific activity of the Factor V activator toward tosyl-L-arginine methyl ester and D-phenylalanyl-L-pipecolyl-L-arginyl-p-nitroanilide was 380 and 11 nmol/min/mg, respectively. The esterase and coagulant activities of the enzyme were readily inhibited by diisopropyl fluorophosphate. The enzyme was not inhibited by bovine antithrombin III in the presence or absence of heparin. The amino acid and carbohydrate compositions of the enzyme are also reported.

Amino Acid Sequence↗
PubMed1979

The effect of Gaboon viper venom on iron exchange in the rat.

Plasma iron turnover (PIT) has been measured by means of 59Fe in rats treated with the haemorrhagic venom of the Gaboon viper (Bitis gabonica). Venom was administered on 3 occasions over a period of 9 days and after this time PIT had fallen from 1045 micrograms/kg/day in normal animals to 449 micrograms/kg/day in envenomated animals. Plasma iron half-life was markedly increased from 64.8 min to 417.6 min and this change was associated with a reduced uptake of 59Fe by the liver. However, marrow and spleen uptake of 59Fe was normal, as were the red-cell indices, MCH, MCV and MCHC. There was a slight reduction in total red-cell numbers and haemoglobin concentration as a result of the mild internal haemorrhage induced by the venom. It is concluded that Gaboon viper venom produces a marked disturbance of iron handling by the liver without an associated change in erythropoiesis. The mild haemorrhage was insufficient to produce a microcytic hypochromic anaemia. The results of the study provide further confirmation of the belief that standard ferrokinetic measurements give only limited information on erythropoietic status.

Animals↗
PubMed1978

Activation of decarboxyfactor X by a protein from Russell's viper venom. Purification and partial characterization of activated decarboxyfactor X.

1. Incubation of decarboxyfactor X with the factor X-activating enzyme from Russell's Viper venom revealed the generation of amidase activity towards Bz-Ile-Glu-Gly-Arg-pNA, but not of activity in blood coagulation. 2. The rate of activation of both factor X and decarboxyfactor X depends on the ability of the zymogens to bind Ca2+. The relationship between Ca2+ concentration and velocity of the activation reaction is sigmoid in the case of factor X, but hyperbolic with decarboxyfactor X. 3. Activated decarboxyfactor X was purified by powder column electrophoresis. 4. Identical changes of primary structure accompanied the activation of factor X and decarboxyfactor X. Identical molecular weight and common antigenic determinants were found in factor Xa and decarboxyfactor Xa. The amino acid composition was identical except for 12 glutamic acid residues in decarboxyfactor Xa and gamma-carboxyglutamic acid residues in factor Xa. 5. Unlike factor X, activated factor X has a very low electrophoretic mobility in the presence of Ca2+ at pH 8.6. This is probably due to self association of factor Xa under the influence of Ca2+. The electrophoretic mobility of activated decarboxyfactor X is only slightly decreased compared to decarboxyfactor X in the presence of Ca2+.

Amidohydrolases↗
PubMed1979

Coagulation abnormalities induced by Russell's viper venom in the rhesus monkey.

Coagulation studies were carried out in a group of non-human primates (rhesus monkeys) following envenomation with lethal and sublethal doses of Russell's viper venom. The envenomated animals showed significant fibrinogenopenia in association with or without disseminated intravascular coagulation. The findings offer a rational explanation for the bleeding manifestations seen in clinical cases of Russell's viper bite.

Afibrinogenemia↗
PubMedDate not supplied

[Preparation and study of properties of immobilized phosphodiesterases from blunt-nosed viper venom].

From gurza poison phosphodiesterase covalently bound with DEAE-cellulose via triazine dye was isolated. Immobilized phosphodiesterase retained 100% activity of the initial enzyme. The effect of pH, temperature. Mg++ concentration on the immobilized enzyme activity was studied. Preparations of the immobilized enzyme did not lose their activity upon hydrolysis of oligodeoxy- and ribonucleotides during a month and remained suitable for prolonged hydrolysis of preparative quantities of oligonucleotides.

Chromatography, DEAE-Cellulose↗
PubMed2026

Genotoxic Activity of Cerastes cerastes Viper Venom Using Alkaline Single-Cell Gel Electrophoresis.

In Morocco, Cerastes cerastes snake is responsible for numerous cases of human envenomation, leading to both local and systemic pathophysiological disturbances. This study provides a first preliminary evaluation of cytotoxic and genotoxic effects of its venom on genomic material (Deoxyribonucleotide acid: DNA). The venom protein profile was characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its median lethal dose (LD50) was determined by intraperitoneal injection in mice. Genotoxicity was assessed using the alkaline comet assay (single-cell gel electrophoresis) on peripheral blood cells following in vitro and in vivo venom treatments with sampling performed between 1 and 24 h after exposure. Concurrently, cell death was evaluated using the trypan blue exclusion assay as an indicator of venom-induced cytotoxicity. DNA damage parameters, including percentage of DNA in the head, tail and tail length, were quantified using OpenComet software. The venom exhibited a protein-rich composition and an LD50 of 34.64 µg/mouse. The comet assay revealed statistically significant DNA damage compared to the control group. Partial to complete DNA repair was noted after 24 h depending on the administered dose. These findings confirm those obtained with cell death assay. All results indicate that Moroccan C. cerastes venom induces transient DNA damage, potentially associated with oxidative stress mechanisms leading to cytotoxicity. It is primordial to characterize target venom-molecules exhibiting genetic failure in order to find an adequate therapeutic approach.

Cerastes cerastes venom↗
PubMed1979

Severe conditioned taste aversion elicited by venom of Russell's viper.

Conditioned taste aversion (CTA) established in rats by associating saccharin drinking with subsequent poisoning by Russell's viper venom. Retention test revealed 76 and 56% reduction of saccharin intake in venom and antivenom-venom groups. No CTA was observed in antivenom and control groups.

Animals↗
PubMed1976

[The effect of pH value and temperature on the stability of L-aminoacidoxidase from the venom of the sand viper].

The stability of highly purified L-amino acid oxidase from the sand viper venom remains practically unaffected by the pH-value at 4degreesC between pH 5 and 8, whereas a sharp activity fall was observed on both sides of this range. At temperatures above 30 degreesC the enzyme is stable only at pH 5.0--5.5. The inactivation pH values above 5.5 follows a first-order rate equation with characteristic changes in the absorption and emission spectra of the enzyme. The stability of the enzyme is dependent on the temperature of storage. At pH 7.5 there is a stability minimum at --10 degrees and -- 30 degreesC. At -- 72 degreesC the enzyme is stable practically for an unlimited period of time; temperatures exceeding 50 degrees C rapidly lead to complete inactivation. Also in the cold, the L-amino acid oxidase is most stable at pH 5.5. There are characteristic changes in absorption and emission spectra in the temperature-stability minimum (--15 degreesC) and at temperatures above 30degreesC. The inactivations follow a first-order rate equation. The cold inactivation is reversible. The stability of the enzyme is diminished by some anions and cations at 37 degreesC. The cold inactivation is promoted by several inorganic anions; organic anions and ammonium sulfate prevent cold inactivation.

Amino Acid Oxidoreductases↗
PubMed1977

Isolation of the high molecular form of bovine factor X and some of its physical properties.

A high molecular form of bovine factor X has been isolated from freshly collected bovine blood by BaSO4 absorption, exhaustive washing with 0.001 M BaCl2 and chromatographed on DEAE-cellulose column employing a linear salt gradient. This isolated factor X showed a single protein band on analytical polyacrylamide gel disc electrophoresis. Only one single protein peak was observed in the chromatogram of DEAE-Sephadex A-50 chromatography conducted at 3 degrees C. Sedimentation equilibrium analysis of this bovine factor X revealed no apparent heterogeneity or self association-dissociation phenomena. It yielded a weight-average molecular weight of 74 000 for the native factor X. In the absence of any reducing agent, factor X migrated in dodecyl sulfate gel electrophoresis as a single component with an estimated molecular weight of 74 300. Both dodecyl sulfate gel electrophoresis in the presence of 2-mercaptoethanol and agarose gel chromatography in 6 M guanidinium chloride revealed that this native factor X is composed of two polypeptide chains of molecular weights of 56 000 and 22 100. Factor X can be converted to the enzymatically active factor Xa by Russell's viper venom and in the presence of Ca2+. Factor Xa was purified by DEAE-cellulose chromatography. This Russell's viper venom activated factor Xa also showed a single protein band upon analytical polyacrylamide gel disc electrophoresis. Sedimentation equilibrium analysis of this factor Xa yields a weight-average molecular weight of 59 000 with no apparent heterogeneity or self-association phenomena. In the absence of any reducing agent, factor Xa migrated as a single component in dodecyl sulfate gel electrophoresis with an estimated molecular weight of 58 500. From the results of dodecyl sulfate gel electrophoresis in the presence of 2-mercaptoethanol as well as agarose gel chromatography in 6 M guanidinium chloride, factor Xa is also composed of two polypeptide chains of molecular weights of 36 700 and 22 800. Therefore, the heavy and light chains of both native factor X and factor Xa are linked together by disulfides. Great care was taken in washing the BaSO4 precipitate and it is this effective washing which enabled us to isolate the higher molecular from of bovine factor X.

Animals↗
PubMed1979

Humoral factor that specifically regulates factor X levels in rabbits (coagulopoietin-X).

A heat-stable humoral substance (coagulopoietin-X) is present in rabbits partially depleted of Factor X, which is capable of raising Factor X levels when injected into recipient rabbits. Rabbits were partially depleted of Factor X by slow infusion of a globulin fraction of goat anti-rabbit Factor X antibody. This resulted in the reduction of Factor X to 40--50% of normal at 1 h and 60--70% of normal at 6 h. No effect was noted on levels of Factors II, V, or VII. Plasma from these animals, when injected into 10 recipients, specifically raised Factor X levels when measured by four different assay: one-stage assay with bovine VII- and X-deficient plasma and Russell's viper venom; one-stage assay with human X-deficient plasma and thromboplastin; chromogenic substrate assay with Russell's viper venom; and an immunologic assay (Laurell technique). No rise was noted in two control experiments in which normal plasma was injected into recipient rabbits from 2 rabbits injected with a globulin fraction of normal goat serum, nor in 12 rabbits injected with plasma from normal rabbits, nor in 5 rabbits injected with boiled plasma from normal rabbits. The rise in biologic activity of 120--150% of base line was significantly greater than the rise in immunologic activity of 114--117% of base line (P less than 0.05) on 3 different days, suggesting the production of a molecule with greater specific activity rather than increased protein synthesis.

Animals↗
PubMed1978

Pit viper snakebite in the United States.

Pit viper snakebite is a relatively uncommon medical emergency which must be adequately diagnosed and treated to minimize local tissue destruction and systemic complications and to prevent death. Severity is highly variable and may range from minimal local pain and swelling to marked pain, edema, tissue necrosis, hemorrhage, shock, and death within one hour. By far, the most common complication is local tissue destruction often resulting in loss of function. Pit viper venom is extremely complex, containing factors which directly destroy muscle, blood vessels, and renal tissues. Other components anticoagulate blood and cause hypotension, local edema, and pain. Neurotoxicity is unusual, but respiratory paralysis may follow Mojave rattlesnake bites. Proper first aid consists of a proximal mildly constricting tourniquet, superficial incision at fang marks, and constant suction. Medical management consists of early intravenous antivenin in adequate dosage, after hypersensitivity testing. Other measures are largely supportive. The early use of corticosteroids is controversial. Cryotherapy is to be avoided. Fasciotomy may be necessary when edema is severe and impairs arterial perfusion. Promising developments include immunization trials against pit viper venom as well as studies on the antivenom activity of rattlesnake plasma.

Adrenal Cortex Hormones↗
PubMed1979

Comparative thermometric coagulation studies of plasmas from normal outbred Swiss Webster mice and persons.

The functional capabilities of a thermometric clot-timer have been demonstrated in a comparative study of human and mouse plasma coagulation. The influence of some variables on coagulation times of mouse and human plasmas were examined in activated partial thromboplastin time, one-stage prothrombin time, and Russell's viper venom time assays. Mouse plasma coagulation times were generally shorter and more reproducible than those of human plasma. Optimal assay conditions are also described.

Animals↗