Anthony T. Tu

Some biochemical evidence in support of the classification of venomous snakes

Abstract Proteolytic enzyme activities of 22 poisonous snake venoms were investigated by using the synthetic substrates, p -toluene-sulfonyl-L-arginine methyl ester and N-benzoyl-L-arginine ethyl ester. Eleven crotalid, three viperid and eight elapid venoms were used. Venoms of Crotalidae and Viperidae showed proteolytic enzyme activity but none of the Elapidae venoms investigated showed this enzyme activity.

Hemorrhagic and proteolytic activities of thailand snake venoms

Abstract Venoms of six common Thailand snakes, Agkistrodon rhodostoma (Malayan pit viper), Trimeresurus popiorum (Green pit viper), Vipera russellii siamensis (Thailand Russells viper), Ophiophagus hannah (King cobra), Bungarus fasciatus (Banded krait), and Naja naja siamensis (Thailand cobra) were investigated for hemorrhagic and proteolytic enzyme activities. Hemorrhage was induced experimentally under rabbit skin by injecting venom subcutaneously. Proteolytic activities of venoms were determined using the substrates casein, p -toluene sulfonyl- l -arginine methyl ester (TAME), N -benzoyl- l -arginine ethyl ester (BAEE), and N -benzoyl-L-tyrosine ethyl ester (BTEE). The possible relationship between hemorrhagic activity and proteolytic activities was discussed.

Proteolytic enzyme activities in a variety of snake venoms

Summary The trypsin-like activity of twenty-five Crotalidae and Viperidae venoms was investigated using p -toluenesulfonyl- l -arginine methyl ester (TAME) and N -benzoyl- l -arginine ethyl ester (BAEE), with and without soybean trypsin inhibitor and ovomucoid. Since hydrolysis of these substrates was not inhibited in the presence of the two inhibitors, the enzymes present in Crotalidae and Viperidae venoms are not identical to trypsin. Chymotrypsin-like activity of thirty-three Crotalidae, Viperidae, and Elapidae venoms was tested using N -benzoyl- l -tyrosine ethyl ester and N -acetyl- l -tyrosine ethyl ester. Most of the venoms did not hydrolyze these substrates. Apparently, there is no chymotrypsin in these snake venoms. Thrombin-like activity was tested using both TAME and BAEE. None of the Crotalidae and Viperidae venoms formed fibrin from fibrinogen even though they hydrolyzed TAME. It is also concluded that the proteolytic enzymes in Crotalidae and Viperidae venoms are similar to each other, while those of Elapidae venoms are different. It is apparent from this investigation that there are new types of proteolytic enzymes whose nature needs further clarification.

Acid and alkaline phosphomonoesterase activities in snake venoms.

Abstract 1. 1. Acid and alkaline phosphatase activities of eight different snake venoms were determined quantitatively by using synthetic substrates, o -carboxyphenylphosphate and p -nitrophenylphosphate respectively. 2. 2. It was found that most of Elapidae venoms investigated had both acid and alkaline phosphatase activities. 3. 3. Three Crotalidae venoms investigated did not show any alkaline phosphatase activity. 4. 4. The strength of venom acid phosphatase activity is as follows: Agkistroden acutus > Naja haje > Naja naja samarensis > Naja naja atra > Naja melanoleuca. 5. 5. The strength of venom alkaline phosphatase activity by using p -nitrophenylphosphate is in the order of Naja hannah > Naja haje > Naja naja samarensis > Naja naja atra > Naja melanoleuca. When o -carboxyphenylphosphate was used as a substrate, the order of enzyme activity is Naja hannah > Naja haje > Naja naja samarensis > Naja melanoleuca > Naja naja atra. 6. 6. Acid phosphatase activity of all the Elapidae venoms was inhibited completely by fluoride. The alkaline phosphatase activity of Elapidae venoms was not inhibited by fluoride either using p -nitrophenylphosphate or o -carboxyphenylphosphate. 7. 7. The acid phosphatase of all the Elapidae venoms was not inhibited by zinc ion. However, most of the venom alkaline phosphatases were inhibited by zinc ion. 8. 8. Ethylenediaminetetraacetic acid (EDTA) had inhibitory action on venom phosphatase activity. However, tris-(hydroxymethyl)-aminoethane had a counter effect on the inhibitory action of EDTA. 9. 9. Optimum pH studies of the snake venom phosphatases showed that the acid phosphatases of the snake venoms had their highest activity in the range of pH 4–5. The alkaline phosphatases of the snake venoms had their optimum pH at 9. 10. 10. Comparable experiments were also conducted by using chicken intestine alkaline phosphatase and wheat germ acid phosphatase.

Protein nature and some enzymatic properties of the lizard Heloderma suspectum suspectum (Gila monster) venom

Abstract 1. 1. Gila monster venom consists mainly of proteins and the toxic principles are found to be non-dialyzable proteins. 2. 2. The venom showed proteolytic enzyme activities and hydrolyzed the synthetic substrates of arginine esters, dipeptides and tripeptides. 3. 3. Fractionation of whole venom on Sephadex G-75 yielded two major peaks. The fraction with high proteolytic activity was found to be toxic while the fraction with no appreciable proteolytic activity was non-toxic.

Peptidase activity of snake venoms

1. 1. Peptidase activities of twenty-one snake venoms were investigated using different dipeptides and tripeptides and tetrapeptide. Venoms used were from seven Elapidae, three Viperidae and eleven Crotalidae. 2. 2. It was found in general that the closer the species of snakes, the more similar were the specificities of the peptidase activities of the venoms. Peptidase specificites of Naja naja samarensis, Naja haje and Naja melanoleuca were exactly identical. Oxyuranus scutellatus and Oxyuranus scutellatus canni venoms also had the same specificities. 3. 3. Peptidase specificity of Vipera russellii venom was very similar to Vipera ammodytes but was different from B. arietabns. 4. 4. The venoms of snakes of North American origin such as Agkintrodon mokasen, Agkistrodon contortrix contortrix, Agkistrodon contortrix laticincus and Agkistrodon contortrix piscivorus were very similar and differed in only one peptide between each other. Venoms of North American rattlesnakes such as Crotalus adamateus, Crotalus atrox and Crotalus viridis oreganus were similar to each other but more different from the Agkistrodon series. 5. 5. Exceptions were Naja naja atra and Agkistrodon acutus of Formosan origin. These venoms were different from those of other snakes in the corresponding genus. 6. None of the venoms investigated contain either carboxypeptidase or aminopeptidase.

Effect of Naja naja atra venom on cytochrome C oxidase, L-ascorbic acid oxidase, peroxidase, and catalase.

Abstract The effects of Naja naja atra venom on cytochrome c oxidase, L-ascorbic acid oxidase, peroxidase, and catalase were investigated. It was found that the venom inhibited cytochrome c oxidase and L-ascorbic acid oxidase but not peroxidase nor catalase.

Hydrolysis of peptides by Crotalidae and Viperidae venoms

Abstract Peptidase activities of nine Viperidae and thirteen Crotalidae venoms were investigated using twenty-nine dipeptides, six tripeptides, and one tetrapeptide. Only five peptides were not hydrolyzed by any of the snake venoms investigated. Relatively few differences in substrate specificities were found for snake venoms regardless of species and geographical distribution.