Displaying all 9 publications

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  1. Tan NH, Ponnudurai G
    Comp. Biochem. Physiol., B, 1991;99(2):351-4.
    PMID: 1764914
    1. The protease, phosphodiesterase, alkaline phosphomonoesterase, L-amino acid oxidase, acetylcholinesterase, phospholipase A, 5'-nucleotidase, hyaluronidase, arginine ester hydrolase, procoagulant, anticoagulant and hemorrhagic activities of ten samples of venoms from seven taxa of sea snakes were examined. 2. The results show that venoms of sea snakes of both subfamilies of Hydrophiinae and Laticaudinae are characterized by a very low level of enzymatic activities, except phospholipase A activity and, for some species, hyaluronidase activity. 3. Because of the low levels of enzymatic activities and the total lack of procoagulant and hemorrhagic activities, venom biological properties are not useful for the differentiation of species of sea snakes. Nevertheless, the unusually low levels of enzymatic activities of sea snake venoms may be used to distinguish sea snake venoms from other elapid or viperid venoms.
    Matched MeSH terms: Phospholipases A/metabolism
  2. Tan NH, Saifuddin MN, Yong WY
    Biochem. Int., 1991 Jan;23(1):175-81.
    PMID: 1863271
    The edema inducing activity of phospholipase A2 (PLA2) enzymes from snake venoms and porcine pancreas was investigated using mouse paw as experimental model. All ten PLA2 enzymes exhibited potent edema inducing activity. PLA2, however, is generally not the major edema inducing component of snake venom. Chemical modification studies indicated that enzymatic activity of PLA2 was required for its edema inducing activity. All PLA2 enzymes examined displayed a rapid onset edema which was suppressed by pretreatment of the mice with antihistamine. Dexamethasone pretreatment also inhibited edemas elicited by some PLA2 enzymes.
    Matched MeSH terms: Phospholipases A/metabolism
  3. Tan NH, Ponnudurai G
    Comp. Biochem. Physiol., B, 1990;96(4):683-8.
    PMID: 2171867
    1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, hyaluronidase, alkaline phosphomonoesterase, 5'-nucleotidase, arginine ester hydrolase, phospholipase A, L-amino acid oxidase and protease activities of 26 samples of venoms of 13 taxa of Vipera were determined and the Sephadex G-75 gel filtration patterns for some of the venoms were also examined. 2. The results indicate the presence of certain common characteristics among the venoms, particularly if V. russelli is excluded from the comparison. The results also support the recently proposed reassignment of V. russelli to a separate genus. 3. The data show that information on venom biological properties can be used for differentiation of venoms of many species of Vipera. Particularly useful for this purpose are the protease, phosphodiesterase, phospholipase A and the procoagulant activities and the Sephadex G-75 gel filtration patterns of the venoms.
    Matched MeSH terms: Phospholipases A/metabolism
  4. Azila N, Othman I
    Biochem. Int., 1990;20(2):291-9.
    PMID: 1969267
    An extract prepared from the tentacle of Catostylus mosaicus was shown to lyse erythrocytes from rat, rabbit and human to a different extent; those from the rat being most susceptible followed by those from rabbit and human. The haemolytic activity was dependent on the concentration of crude extract protein exhibiting a sigmoidal curve. Only 60% of the haemolytic activity was retained after treament with heat and proteolytic enzyme. The extract was devoid of hydrolytic enzymes normally present in venoms except for phospholipase A activity, which resulted in the hydrolysis of membrane phospholipids with concomittant appearance of their lyso-derivatives.
    Matched MeSH terms: Phospholipases A/metabolism*
  5. Tan NH, Ponnudurai G
    PMID: 1676959
    1. The hemorrhagic, procoagulant, anticoagulant, protease, arginine ester hydrolase, phosphodiesterase, alkaline phosphomonoesterase, 5'-nucleotidase, hyaluronidase, phospholipase A and L-amino acid oxidase activities of 50 venom samples from 20 taxa of rattlesnake (genera Crotalus and Sistrurus) were examined. 2. The results show that notwithstanding individual variations in the biological activities of Crotalus venoms and the wide ranges of certain biological activities observed, there are some common characteristics at the genus and species levels. 3. The differences in biological activities of the venoms compared can be used for differentiation of the species. Particularly useful for this purpose are the thrombin-like enzyme, protease, arginine ester hydrolase, hemorrhagic and phospholipase A activities and kaolin-cephalin clotting time measurements.
    Matched MeSH terms: Phospholipases A/metabolism
  6. Nget Hong Tan, Chon Seng Tan, Hun Teck Khor
    Int. J. Biochem., 1989;21(12):1421-6.
    PMID: 2612728
    1. The major phospholipase A2 (PLA-DE4) of the venom of Trimeresurus purpureomaculatus (shore pit viper) has been purified to electrophoretic homogeneity. 2. The isoelectric point of the purified enzyme was determined to be 4.20, and the mol. wt was 31,700 as estimated by Sephadex G-75 gel filtration chromatography; and 14,000 as estimated by SDS-polyacrylamide gel electrophoresis. The purified enzyme hydrolyzed phosphatidylcholine (PC) faster than phosphatidylethanolamine (PE), whereas phosphatidylserine (PS) was not hydrolyzed at all (PC greater than PE greater than PS =0). However, in reaction system consisted of mixtures of PC and PS, phosphatidylserine was effectively hydrolyzed by the enzyme. 4. The phospholipase A2 exhibited edema-forming activity but not hemolytic, hemorrhagic or anticoagulant activities. It was not lethal to mice at a dosage of 10 micrograms/g by i.v. route.
    Matched MeSH terms: Phospholipases A/metabolism
  7. Tan NH, Armugam A, Tan CS
    Comp. Biochem. Physiol., B, 1989;93(4):757-62.
    PMID: 2553329
    1. The lethalities, anticoagulant effects, hermorrhagic, thrombin-like enzyme, hyaluronidase, protease, arginine ester hydrolase, 5'-nucleotidase, L-amino acid oxidase, alkaline phosphomonoesterase, phosphodiesterase and phospholipase A activities of twenty-three samples of venoms from twelve species of Asian lance-headed pit vipers (genus Trimeresurus) were examined. 2. The results indicate that notwithstanding individual variations in venom properties, the differences in biological properties of the Trimeresurus venoms can be used for the differentiation of venoms from different species of Trimeresurus. 3. The results also suggest that differences in the biological properties of snake venoms are useful parameters in the classification of snake species. 4. Our results indicate that venoms from the species T. okinavensis exhibited biological properties markedly different from other Trimeresurus venoms examined. This observation supports the recently proposed reclassification of T. okinavensis as a member of the genus Ovophis, rather than the genus Trimeresurus.
    Matched MeSH terms: Phospholipases A/metabolism
  8. Tan NH, Ponnudurai G
    Comp. Biochem. Physiol., B, 1990;95(3):577-82.
    PMID: 2158874
    1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, alkaline phosphomonoesterase, 5'-nucleotidase, hyaluronidase, arginine ester hydrolase, phospholipase A, L-amino acid oxidase and protease activities of 31 samples of venom from three species of Agkistrodon (A. bilineatus, A. contortrix and A. piscivorus) and 10 venom samples from five other related species belonging to the same tribe of Agkistrodontini were examined. 2. The results indicate that interspecific differences in certain biological activities of the Agkistrodon venoms are more marked than individual variations of the activities, and that these differences can be used for differentiation of the species. Particularly useful for this purpose are the phosphodiesterase, arginine ester hydrolase and anticoagulant activities of the venoms. 3. Venoms of the subspecies of A. contortrix and A. piscivorus do not differ significantly in their biological activities.
    Matched MeSH terms: Phospholipases A/metabolism
  9. Tan NH, Ponnudurai G
    PMID: 1971550
    1. The intravenous median lethal doses (LD50), protease, phosphodiesterase, alkaline phosphomonoesterase, L-amino acid oxidase, acetylcholinesterase, phospholipase A, 5'-nucleotidase, hyauronidase and anticoagulant activities of fourteen samples of venoms from the four common species of krait (Bungarus caeruleus, Bungarus candidus, Bungarus multicinctus and Bungarus fasciatus) were examined. 2. The results indicate that even though there are individual variations in the biological properties of the krait venoms, interspecific differences in the properties can be used for differentiation of the venoms from the four species of Bungarus. Particularly useful for this purpose are the LD50's and the contents of 5'-nucleotidase and hyaluronidase of the venoms.
    Matched MeSH terms: Phospholipases A/metabolism
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