Effect of calcium on proteolytic activity and conformation of hemorrhagic toxin I from five pace snake (Agkistrodon acutus) venom

J. J. Zhang, Z. X. Chen, Y. Z. He and X. Xu. Effect of calcium on proteolytic activity and conformation of hemorrhagic toxin I from five pace snake (Agkistrodon acutus) venom. Toxicon22, 931–935, 1984. — AaHI, a proteolytic hemorrhagic toxin from A. acutus venom, contains one g-atom Zn per mole protein and 2 g-atoms Ca per mole protein. AaHI is activated by calcium and slightly inhibited by zinc. When treated with EDTA, AaHI is completely inactivated. When dialyzed against 1,10-O-phenanthroline, 50–80% of the metal content and activities are lost, while 90% of the hemorrhagic and proteolytic activities are retained when dialyzed against 1,10-O-phenanthroline containing 5mM Ca²⁺. The results suggest that calcium is essential for the hemorrhagic and proteolytic activities. The circular dichroism spectra show that calcium may play an important role in maintaining a proper structure for AaHI. The function of zinc is not clear.     

Purification and characterization of hemorrhagic components from Agkistrodon acutus (hundred pace snake) venom

Three toxic components, designated Aa-hemorrhagin I,II,III, were isolated from the venom of Agkistrodon acutus by DEAE-Sephadex A-50 chromatography and were further purified by gel filtration on Sephadex G-75, and by column chromatography on DE52 cellulose and CM-Sephadex C-25. All of these components show single bands on acrylamide gel electrophoresis and one precipitin line on immunoelectrophoresis. They are distinct from each other immunochemically. Aa-hemorrhagin I and II are acidic proteins, while III is basic. These hemorrhagins have similar mol. wts of about 22,000. In addition to hemorrhagic and lethal activities, these hemorrhagins possess caseinolytic activities. Their hemorrhagic and caseinolytic activities are inhibited by EDTA, cysteine and the serum of homologous snakes. The amino acid composition of the Aa-hemorrhagin I was determined.     

α-Fibrinogenase from Agkistrodon rhodostoma (Malayan pit viper) snake venom

By means of DEAE-Sephadex A-50 column chromatography, Agkistrodon rhodostoma (Malayan pit viper) snake venom was separated into eleven fractions. Fraction II had fibrinogenolytic activity, and when further purified by gel filtration was homogeneous, as judged by sodium dodecylsulfate polyacrylamide gel electrophoresis. It had a single peptide chain with a molecular weight of 25,360 and an isoelectric point greater than 10. The fibrinogenolytic activity was completely destroyed after heating for 30 min at 60°C at pH 5.6, 7.4 or 8.8. This enzyme cleaved specifically the α(A) chain of monomeric fibrinogen, without cleaving the β(B) chain or γ chain. The specific fibrinogenolytic activity was 51 mg fibrinogen/min per mg protein. This enzyme showed proteolytic activities toward fibrinogen, fibrin and casein, but was devoid of phospholipase A and tosyl-l-arginine methylester esterase activities which are found in the crude venom. The fibrinogenolytic activity was inhibited by EDTA and cysteine, but not by ε-aminocaproic acid.     

Characterization of hemorrhagic principles from Trimeresurus gramineus snake venom

In addition to alpha-fibrinogenase (hemorrhagin I, HR1), a potent hemorrhagic principle (hemorrhagin II, HR2) was purified from Trimeresurus gramineus venom. It was homogeneous as judged by SDS-polyacrylamide gel electrophoresis. HR2 was a single peptide chain containing 10% carbohydrate with a molecular weight of 81,500. It possessed 669 amino acid residues per molecule, while HR1 contained only 203 amino acid residues per molecule with a molecular weight of 23,500. Both hemorrhagins possessed proteolytic activities toward fibrinogen, casein and azocoll. However, the proteolytic activities of HR1 were much more potent than those of HR2. They were devoid of TAME-esterase and phospholipase A2 activities which were found in crude venom. beta-Mercaptoethanol and antivenin completely inhibited the hemorrhagic activities of HR1 and HR2, while epsilon-aminocaproic acid, trasylol, p-bromophenacyl bromide, phenylmethanesulfonyl fluoride and soybean trypsin inhibitor did not. EDTA completely inhibited the hemorrhagic, fibrinogenolytic and caseinolytic activities of HR1. EDTA also completely inhibited the caseinolytic and fibrinogenolytic activities of HR2, but only partially inhibited its hemorrhagic activity. Subsequent addition of Zn2+ (5 mM) reversed the EDTA-induced inhibitory effect on the hemorrhagic activity of HR1. However, ZN2+ did not reverse the EDTA-induced inhibitory effect on the HR2-induced hemorrhagic activity. These hemorrhagins were found to be ZN2+-containing metalloproteinases. Therefore, the hemorrhagic activity of HR1 seems to be related to its proteolytic activity while that of HR2 seems to be unrelated to its proteolytic activity.     

Purification and characterization of a hemorrhagic metalloproteinase from Bothrops lanceolatus (Fer-de-lance) snake venom.

Bothrops snake venoms contain metalloproteinases that contribute to the local effects seen after envenoming. In this work, a hemorrhagic metalloproteinase (BlaH1) was purified from the venom of the snake Bothrops lanceolatus by a combination of gel filtration, affinity (metal chelating) and hydrophobic interaction chromatographies. The hemorrhagin was homogeneous by SDS-PAGE and had a molecular mass of 28 kDa that was unaltered by treatment with beta-mercaptoethanol. BlaH1 gave a single band in immunoelectrophoresis and immunoblotting using commercial bothropic antivenom. BlaH1 had hemorrhagic, caseinolytic, fibrinogenolytic, collagenolytic and elastinolytic activities, but no phospholipase A(2) activity. The hemorrhagic and caseinolytic activities were inhibited by EDTA, indicating that they were metal ion-dependent. In contrast, aprotinin, benzamidine and PMSF did not affect these activities. The caseinolytic activity of BlaH1 had a pH optimum of 8.0 and was stable in solution at up to 40 degrees C; activity was completely lost at > or =70 degrees C. The hemorrhagic activity was neutralized by commercial bothropic antivenom. These properties suggest that this new hemorrhagin belongs to class P-I snake venom metalloproteinases.     

The effect of the purified anticoagulant principle of Agkistrodon acutus venom on blood coagulation

The purified anticoagulant principle of Agkistrodon acutus venom had marked anticoagulant action when tested on whole blood clotting time, calcium clotting time and plasma prothrombin time. It did not destroy fibrinogen, induce fibrinolysis, inactivate thrombin nor interfere with the interaction between thrombin and fibrinogen. However a marked inhibition of prothrombin activation was not due to the destruction of prothrombin or its activation factors, but due to an interference in the interaction between prothrombin and its activation factors because of the reversible binding of these factors with the anticoagulant principle of the venom.     

Snake venom NAD nucleosidase: its occurrence in the venoms from the genus Agkistrodon and purification and properties of the enzyme from the venom of A. halys blomhoffii.

Nicotinamide adenine dinucleotide nucleosidase (NAD glycohydrolase, EC 3.2.2.5) was demonstrated in venoms of various snakes. Among the venoms from 37 species of Viperidae, Crotalidae and Elapidae, venom of snakes in the genera Bungarus and Agkistrodon showed the highest activities. No NAD nucleosidase activity was detected in venoms of the Naja genus.A NAD nucleosidase found in the venom of Agkistrodon halys blomhoffii was purified by successive column chromatographies on DEAE-cellulose and DEAE-Sephadex A-50 and gel-filtration on Sepharose 6B. Final purification was over 25-fold with 20 per cent yield. The purified enzyme showed maximal activity at pH 7.5 and hydrolysed β-NAD⁺, NADP⁺ and 3-acetylpyridine adenine dinucleotide. No hydrolysis could be observed on α-NAD⁺, NADH, NADPH and NMN⁺. The Km values for β-NAD⁺, NADP⁺ and 3-acetylpyridine adenine dinucleotide were 8.3 × 10^?4 M and 7.4 × 10^?4 M, respectively. Over 60 per cent inhibition of β-NAD⁺ hydrolysis was observed in the presence of 10^?3 M of HgCl₂ and cysteine.     

五步蛇蛇毒纤溶组分Ⅱ的分离和若干药效学的特征

五步蛇蛇毒经DEAE—sephadex A—50柱层析.获得15个蛋白组分。sephadex G—50柱再层析组分Ⅱ,呈单一个蛋白峰,聚丙酰胺凝胶电泳结果呈单一区带。狗血浆纤维蛋白平板法证实五步蛇蛇毒组分Ⅱ有溶解纤维蛋白的作用,同时狗血浆纤维蛋白热平板法还证实其溶解纤维蛋白的作用系直接性的。体外试管实验显示组分Ⅱ虽对纤维蛋白和纤维蛋白原均有溶解作用.但在浓度17.8mg·L~(-1)以下时.其溶解纤维蛋白活性相对较高。兔scO.1ml(500mg·L~(-1)组分Ⅱ未发现类似五步蛇全毒的出血反应。小白鼠腹腔注射纯化后的组分Ⅱ,LD_(50)为11.105 mg,kg~(-1).     

Simplified procedures for the isolation of HF3, bothropasin, disintegrin-like/cysteine-rich protein and a novel P-I metalloproteinase from Bothrops jararaca venom

HF3 and bothropasin are P-III hemorrhagic snake venom metalloproteinases (SVMPs) of Bothrops jararaca. The DC protein is composed of the disintegrin-like/cysteine-rich domains derived from the autolysis of P-III SVMPs. Here we describe simplified procedures for the isolation of HF3, bothropasin, the DC protein, and BJ-PI, a novel P-I SVMP. The isolated proteins were identified by mass spectrometry. BJ-PI is a potent caseinolytic enzyme devoid of hemorrhagic activity. HF3, bothropasin and BJ-PI show distinct fibrinogenolytic activities.     

Thrombin-like and fibrinolytic enzymes in the venoms from the Gaboon viper (Bitis gabonica), eastern cottonmouth moccasin (Agkistrodon p. piscivorus) and southern copperhead (Agkistrodon c. contortrix) snakes

Crude venom from B. gabonica contained weak fibrinogen clotting activity but no visible fibrinolytic activity, whereas venoms from A. p. piscivorus and A. c. contortrix exhibited fibrinolytic activity (by fibrin plate assay) but no thrombin-like activity. These snake venoms were fractionated on Sephadex G-100 with the following results. Thrombin-like activity in B. gabonica venom was eluted in a single protein peak with a molecular weight of 40,000. Agkistrodon p. piscivorus venom contained a single peak of fibrinolytic activity with a molecular weight of 34,000. Interestingly, venom f^rom A. c. contortrix, which showed no thrombin-like activity in crude venom, contained both thrombin-like and fibrinolytic activities in fractions with molecular weights of 73,500 and 25,000 respectively. No plasminogen activation activity was observed in any of the crude venoms or venom fractions eluted from G-100. In view of the possible clinical potential of these enzymes as defibrinogenating or thrombolytic agents, it will be of great interest to further purify and characterize them.     

Dispholidus typus (bommslang) snake venom: purification and properties of the coagulant principle

Peter C. Hiestand and Rosemarie R. Hiestand, Dispholidus typus (Boomslang) snake venom: purification and properties of the coagulant principle. Toxicon17, 489–498, 1979.—Dispholidus typus venom was fractionated into five fractions by means of CM-cellulose column chromatography. Fraction 1 exhibited strong coagulant activity on citrated rabbit plasma. This fraction was further purified by means of preparative isoelectric focusing, DEAE-cellulose chromatography, and gel filtration on Sephadex G-200. After gel filtration two fractions (fraction c and d) containing coagulant activity were obtained. Fraction d separated on disc gel electrophoresis at pH 8·3 into six bands of which one (d₁) coincided with fraction c upon isoelectric focusing and SDS¹ gel electrophoresis. Fraction c which contains the main coagulant activity in Dispholidus typus venom was homogeneous on disc gel electrophoresis and on isoelectric focusing. The molecular weight estimated by gel filtration on Sephadex G-200 was 55,000 and by electrophoresis in sodium dodecyl sulfate 67,000. The isoelectric point was pH 4·4. Chemical analysis showed that fraction c was a thermolabile glycoprotein. Its coagulant activity was approximately 10 times higher than that of crude venom since the active fractions account for ca. 10% of material found in crude dry venom. Although it did exhibit most of the coagulant activity, fraction c did not possess any of the caseinolytic or BAEE²-hydrolyzing activities found in crude venom.     

Caseinolytic and esteratic activities of Malayan pit viper venom and its proteolytic and thrombin-like fractions

Some enzymic activities of the venom of the Malayan pit viper (Agkistrodon rhodostoma) and its two major components were studied. The proteolytic component had strong caseinolytic activity but little esteratic activity using $\text{p-}\text{toluene sulphonyl-}\text{L}\text{-arginine methyl}$ ester (TAME) and N-benzoyl-L-arginine ethyl ester (BAEE) as substrates. On the other hand, the thrombin-like component had marked activity on TAME and BAEE but no caseinolytic activity.     

Ammodytase, a metalloprotease from Vipera ammodytes ammodytes venom, possesses strong fibrinolytic activity

Ammodytase, a high molecular mass metalloproteinase with fibrinogenolytic and fibrinolytic activities, was purified from long-nosed viper (Vipera ammodytes ammodytes) venom by gel filtration, affinity and ion-exchange chromatographies. The enzyme is a single-chain glycoprotein with apparent molecular mass of 70 kDa and isoelectric point of 6.6. Ammodytase shows very weak hemorrhagic activity, and only at doses higher than 20 μg. Consistent with this, it partially degrades some components of the extracellular matrix in vitro. It cleaves the Aα-chain of fibrinogen preferentially at peptide bonds Glu⁴⁴¹-Leu⁴⁴² and Glu⁵³⁹-Phe⁵⁴⁰. Its preference for bulky and hydrophobic amino acids at the P1′ position in substrates is demonstrated by its hydrolysis of only the Gln⁴-His⁵ and Tyr¹⁶-Leu¹⁷ bonds in the B-chain of insulin. Ammodytase is able to dissolve fibrin clots. It neither activates nor degrades plasminogen and prothrombin, and has no effect on collagen- or ADP-induced platelet aggregation in vitro. LC/MS and MS/MS analyses of its tryptic fragments demonstrated that ammodytase is a P-III class snake venom metalloproteinase composed of metalloproteinase, disintegrin-like and cysteine-rich domains. Its similarity to hemorrhagins from V. a. ammodytes venom, accompanied by very low toxicity, makes ammodytase a promising candidate as an antigen to prepare antisera against these most dangerous components of the viper's venom. Moreover, its ability to degrade fibrin clots suggests its clinical use as an antithrombotic agent.     

Crystal structure and activating effect on RyRs of AhV_TL-I, a glycosylated thrombin-like enzyme from Agkistrodon halys snake venom

A snake venom thrombin-like enzyme (SVTLE) from Agkistrodon halys pallas venom was isolated by means of a two-step chromatographic procedure. The purified enzyme, named AhV_TL-I, showed fibrinogenolytic activity against both the Aα and Bβ chains of bovine fibrinogen. Unlike the other SVTLEs, AhV_TL-I has poor esterolytic activity upon BAEE substrate. The N-terminal sequence of AhV_TL-I was determined to be IIGGDEXNINEHRFLVALYT, and the molecular mass was confirmed to 29389.533 Da by MALDI-TOF mass spectrometry. Its complete cDNA and derived amino acid sequence were obtained by RT-PCR. The crystal structure of AhV_TL-I was determined at a resolution of 1.75 Å. A disaccharide was clearly mapped in the structure, which involved in regulating the esterolytic activity of AhV_TL-I. The presence of the N-glycan deformed the 99-loop, and the resulting steric hindrances hindered the substrates to access the active site. Furthermore, with the carbohydrate moiety, AhV_TL-I could induce mouse thoracic aortic ring contraction with the EC₅₀ of 147 nmol/L. Besides, the vasoconstrictor effects of AhV_TL-I were also independent of the enzymatic activity. The results of [Ca²⁺]_i measurement showed that the vasoconstrictor effects of AhV_TL-I were attributed to Ca²⁺ releasing from Ca²⁺ store. Further studies showed that it was related to the activation of ryanodine receptors (RyRs). These offer new insights into the snake SVTLEs functions and provide a novel pathogenesis of A. halys pallas venom.     

尖吻蝮蛇毒研究进展

尖吻蝮(又名五步蛇,中药材名为蕲蛇)蛇毒,是从尖吻蝮毒腺中分泌的毒液,内含磷脂酶A₂、丝氨酸蛋白酶、金属蛋白酶、C型凝集素、L-氨基酸氧化酶等多种蛋白类成分和肽类成分,具有多种生物活性,在抗肿瘤、抗血栓、抗炎、抗菌等方面发挥着重要作用。近年来,蛇毒研究日益广泛,但目前仍缺乏对尖吻蝮蛇毒全面系统的研究。本文通过检索尖吻蝮蛇毒的相关研究进展,在其来源、鉴别、活性成分、毒性研究及质量研究等方面进行总结与分析,以期为尖吻蝮蛇毒进一步开发利用提供参考。     

The Direct Actinc α-Fibrin(Ogen)Olytic Enzymes from Snake Venoms

Abstract

A variety of α-fibrin(ogen)olytic enzymes have been found in snake venoms. More than 15 α-fibrin(ogen)ases have been isolated and characterized. Most work has been done with the venom of snakes belonging to a few species from the Agkistrodon, Crotalus, Trimeresurus, Bothrops, and Vipera. Only one α-fibrin(ogen)olytic enzyme is characterized from Elapidae snake venoms. The enzymatic properties of these proteinases are described in relation to action on fibrinogen, fibrin, and casein. The fibrinolytic enzymes act directly on fibrin and do not activate plasminogen. The proteolytic activity of these metalloproteinases is inhibited by EDTA. Most thoroughly investigated snake venom fibrinolytic enzymes are fibrolase from Agkistrodon contortrix contortrix venom, atroxase from Crotalus atrox venom and cerastase from Cerastes cerastes venom. Antibodies to fibrolase were prepared and their cross-reactions with other fibrinolytic components from several snake venoms have been detected. These antibodies were successfully used for purification of fibrolase from crude southern copperhead venom. Fibrolase and atroxase have no hemorrhagic activity, and they effectively solubilize artificial thrombi. Research in this area has a chance to provide new therapeutic agents for dissolving thrombi.     

Isolation and biological characterization of Batx-I, a weak hemorrhagic and fibrinogenolytic PI metalloproteinase from Colombian Bothrops atrox venom

A hemorrhagic metalloproteinase, named Batx-I, was isolated from the venom of Bothrops atrox specimens (from Southeastern Colombian region) by a combination of CM-Sephadex C25 ion-exchange and Affi-gel Blue affinity chromatographies. This enzyme accounts for about 45% of venom proteins, and it has an ESI-MS isotope-averaged molecular mass of 23296.2 Da and a blocked N-terminus. Two internal fragments sequenced by mass spectrometric analysis showed similarity to other SVMPs from Bothrops venoms. To investigate the possible participation of Batx-I in the envenomation pathophysiology, proteolytic, fibrinogenolytic, hemorrhagic, and other biological activities were evaluated. The minimal hemorrhagic dose obtained was 17 μg/20 g body weight. The enzyme showed proteolytic activity on azocasein, comparable with activity of BaP1. This activity was inhibited by EDTA and 1, 10 o-phenanthroline but not by aprotinin, pepstatin A or PMSF. Fibrinogenolytic activity was analyzed by SDS-PAGE, revealing a preference for degrading the Aα- and Bβ-chains, although partial degradation of the γ-chain was also detected. The protein lacks coagulant and defibrinating activity. The CK levels obtained, clearly reflects a myotoxic activity induced by Batx-I. The hemorrhagic and fibrinogenolytic activities exhibited by the isolated PI-SVMP may play a role in the hemorrhagic and blood-clotting disorders observed in patients bitten by B. atrox in Colombia.     

Hemostatic properties of Venezuelan Bothrops snake venoms with special reference to Bothrops isabelae venom

In Venezuela, Bothrops snakes are responsible for more than 80% of all recorded snakebites. This study focuses on the biological and hemostatic characteristics of Bothrops isabelae venom along with its comparative characteristics with two other closely related Bothrops venoms, Bothrops atrox and Bothrops colombiensis. Electrophoretic profiles of crude B. isabelae venom showed protein bands between 14 and 100 kDa with the majority in the range of 14-31 kDa. The molecular exclusion chromatographic profile of this venom contains five fractions (F1-F5). Amidolytic activity evaluation evidenced strong thrombin-like followed by kallikrein-like activities in crude venom and in fractions F1 and F2. The fibrinogenolytic activity of B. isabelae venom at a ratio of 100:1 (fibrinogen/venom) induced a degradation of Aα and Bβ chains at 15 min and 2 h, respectively. At a ratio of 100:10, a total degradation of Aα and Bβ chains at 5 min and of γ chains at 24 h was apparent. This current study evidences one of rarely reported for Bothrops venoms, which resembles the physiologic effect of plasmin. B. isabelae venom as well as F2 and F3 fractions, contain fibrinolytic activity on fibrin plate of 36, 23.5 and 9.45 mm²/μg, respectively using 25 μg of protein. Crude venom and F1 fraction showed gelatinolytic activity. Comparative analysis amongst Venezuelan bothropoid venoms, evidenced that the LD₅₀ of B. isabelae (5.9 mg/kg) was similar to B. atrox-Puerto Ayacucho 1 (6.1 mg/kg) and B. colombiensis-Caucagua (5.8 mg/kg). B. isabelae venom showed minor hemorrhagic activity, whereas B. atrox-Parguasa (Bolivar state) was the most hemorrhagic. In this study, a relative high thrombin-like activity was observed in B. colombiensis venoms (502-568 mUA/min/mg), and a relative high factor Xa-like activity was found in B. atrox venoms (126-294 mUA/min/mg). Fibrinolytic activity evaluated with 10 μg protein, showed that B. isabelae venom contained higher specific activity (50 mm²/μg) than B. colombiensis and B. atrox venoms, which should encourage the isolation of these fibrinolytic molecules to improve the quality of immunotherapy.     

尖吻蝮蛇毒无出血活性纤溶酶对动物血栓的溶栓作用

目的　研究尖吻蝮蛇毒 (Agkistrodonacutus)无出血活性的纤溶酶对动物血栓形成的溶栓作用。方法　采用家兔动物血栓和大白鼠静脉血栓模型 ,静脉注射尖吻蝮蛇无出血活性纤溶酶 ,分 3个剂量组 (n =6) ,其剂量分别为 0 1 4、0 7、1 4mg·kg- 1 ,用生理盐水作阴性对照。测定尖吻蝮蛇毒无出血活性的纤溶酶对动脉血栓、静脉血栓的溶栓作用。结果　给药后 ,尖吻蝮蛇毒无出血活性的纤溶酶对动脉血栓、静脉血栓湿重均有减轻作用 ,与生理盐水对照组相比 ,差异均有显著性 (P <0 0 5或P <0 0 1 )。结论　尖吻蝮蛇无出血活性纤溶酶对动物血栓有明显的溶栓作用 ,具有潜在的临床应用价值     

Purification and properties of a lethal,hemorrhagic protein, “Mucrotoxin A”, from the venom of the Chinese habu snake (Trimeresurus mucrosquamatus)

Mucrotoxin A was purified from the lyophilized venom of Trimeresurus mucrosquamatus using gel filtration on a Sephadex G-100 column, followed by chromatography on CM-Sephadex C-50 and DEAE-Sephadex A-50. By these procedures, 14 mg of purified preparation could be obtained from 1 g of crude venom. The purified preparation was homogeneous by disc electrophoresis on polyacrylamide gel at pH 8.3, isoelectric focusing and by the presence of one precipitin line on immunodiffusion. Mucrotoxin A possessed both lethal and hemorrhagic activities, but it did not show caseinolytic activity. Its molecular weight was approximately 94,000 and the isoelectric point was 4.3. Mucrotoxin A contains approximately 3 moles of Ca and 2 moles of Zn per mole of toxin. The amino acid composition of Mucrotoxin A was determined. No carbohydrate was present.