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Functional venomics of the Sri Lankan Russell's viper (Daboia russelii) and its toxinological correlations

Tan NH, Fung SY, Tan KY, Yap MK, Gnanathasan CA, Tan CH

J Proteomics, 2015 Oct 14;128:403-23.

PMID: 26342672 DOI: 10.1016/j.jprot.2015.08.017

The venom proteome (venomics) of the Sri Lankan Daboia russelii was elucidated using 1D SDS PAGE nano-ESI-LCMS/MS shotgun proteomics. A total of 41 different venom proteins belonging to 11 different protein families were identified. The four main protein families are phospholipase A2 (PLA2, 35.0%), snaclec (SCL, 22.4%, mainly platelet aggregation inhibitors), snake venom serine proteinase (SVSP, 16.0%, mainly Factor V activating enzyme) and snake venom metalloproteinase (SVMP, 6.9%, mainly heavy chain of Factor X activating enzyme). Other protein families that account for more than 1% of the venom protein include l-amino acid oxidase (LAAO, 5.2%), Kunitz-type serine proteinase inhibitor (KSPI, 4.6%), venom nerve growth factor (VNGF. 3.5%), 5'-nucleotidase (5'NUC, 3.0%), cysteine-rich secretory protein (CRISP, 2.0%) and phosphodiesterase (PDE, 1.3%). The venom proteome is consistent with the enzymatic and toxic activities of the venom, and it correlates with the clinical manifestations of Sri Lankan D. russelii envenomation which include hemorrhage, coagulopathy, renal failure, neuro-myotoxicity and intravascular hemolysis. The venom exhibited remarkable presypnatic neurotoxicity presumably due to the action of basic PLA2 in high abundance (35.0%). Besides, SCLs, Factor X activating enzymes (SVMPs), SVSPs, and LAAOs are potential hemotoxins (50.5%), contributing to coagulopathy and hemorrhagic syndrome in Sri Lankan D. russelii envenomation.

The role of transvaginal sonography in the diagnosis of placenta praevia

Tan NH, Abu M, Woo JL, Tahir HM

Aust N Z J Obstet Gynaecol, 1995 Feb;35(1):42-5.

PMID: 7771998 DOI: 10.1111/j.1479-828x.1995.tb01828.x

Transvaginal sonography was performed in 70 patients diagnosed to have placenta praevia by transabdominal sonography. The diagnosis was confirmed either by digital examination in theatre at term or operative finding at delivery. Forty-nine cases (70%) were correctly diagnosed to have placenta praevia by both modes of sonography. Transvaginal sonography ruled out placenta praevia in 12 cases (17%) thought to be placenta praevia by transabdominal ultrasound. Both transabdominal and transvaginal sonography demonstrated 'placental migration' in 4 cases (6%) which were no longer praevia at delivery. Five patients (7%) were erroneously believed to have placenta praevia by both sonographic techniques. Overall, the diagnostic accuracy of transvaginal sonography was 92.8% compared with 75.7% for transabdominal sonography. None of the subjects experienced any exacerbation of bleeding or other complications. The results suggest that transvaginal sonographic localization of the placenta is safe and superior to the transabdominal route.

Purification and properties of the L-amino acid oxidase from monocellate cobra (Naja naja kaouthia) venom

Tan NH, Swaminathan S

Int. J. Biochem., 1992 Jun;24(6):967-73.

PMID: 1612186

1. The L-amino acid oxidase of the monocellate cobra (Naja naja kaouthia) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was 112,200 as determined by Sephadex G-200 gel filtration chromatography, and 57,400 as determined by SDS-polyacrylamide gel electrophoresis. 2. The enzyme had an isoelectric point of 8.12 and a pH optimum of 8.5. It showed remarkable thermal stability, and, unlike many venom L-amino acid oxidase, was also stable in alkaline medium. The enzyme was partially inactivated by freezing. 3. The enzyme was very active against L-phenylalanine and L-tyrosine, moderately active against L-tryptophan, L-methionine, L-leucine, L-norleucine, L-arginine and L-norvaline. Other L-amino acids were oxidized slowly or not oxidized. 4. Kinetic studies suggest the presence of a side-chain binding site in the enzyme, and that the binding site comprises of at least four hydrophobic subsites.

A comparative study on the biological properties of venoms from juvenile and adult common tiger snake (Notechis scutatus) venoms

Tan NH, Ponnudurai G, Mirtschin PJ

Comp. Biochem. Physiol., B, 1993 Nov;106(3):651-4.

PMID: 8281760

1. The biological properties of venoms from juvenile and adult common tiger snakes (Notechis scutatus) were compared. 2. The lethality, procoagulant activity and enzymatic activities of the juvenile venom were not substantially different from those of the adult venom. 3. Electrophoretic studies, however, indicated some minor differences in the protein composition of the juvenile and adult venoms.

A comparative study of the biological properties of venoms of some old world vipers (subfamily viperinae)

Tan NH, Ponnudurai G

Int. J. Biochem., 1992 Feb;24(2):331-6.

PMID: 1733799

1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, hyaluronidase, alkaline phosphomonoesterase, 5'-nucleotidase, arginine ester hydrolase, phospholipase A, L-amino acid oxidase and protease activities of 30 samples of venoms from nine species (12 taxa) of the old world vipers (Subfamily Viperinae) including snakes from the genera Bitis, Causus, Cerastes, Echis, Eristicophis and Pseudocerastes, were determined and the Sephadex G-75 gel filtration patterns for some of the venoms were also examined. 2. Examination of the biological properties of the venoms of the Viperinae tested indicates the presence of common venom biological characteristics at the various phylogenic levels. 3. Venoms of most species of the Viperinae examined exhibited characteristic biological properties at the species level, and this allows the differentiation of the Viperinae species by differences in their biological properties. 4. Particularly useful for this purpose, are the effects of venom on kaolin-cephalin clotting time of platelet poor rabbit plasma and the Sephadex G-75 gel filtration pattern and arginine ester hydrolase activity of the venom.

Sociobiological risk factors for spontaneous abortion in Malaysia

Tan NH, Yahya A, Adeeb N

J Obstet Gynaecol (Tokyo 1995), 1995 Aug;21(4):313-8.

PMID: 8775898

OBJECTIVE: To evaluate the risk factors of spontaneous abortion.

METHODS: A case-control study was conducted by interviewing 350 women who were admitted to the university gynaecological unit for spontaneous abortion and 350 women who delivered normally at the university obstetric unit. Odds ratios, as the estimators of relative risks, were calculated.

RESULTS: The relative risk for spontaneous abortion among women in the age-group 30 to 39 years was 1.61 and among women above 40 years of age was 3.68 when compared to those below 30 years of age. In relation to career women, the relative risk of spontaneous abortion for housewives was 0.45. Ethnic group, parity, subfertility, previous induced abortion, ectopic pregnancy, contraception and menarcheal age did not influence the risk of spontaneous abortion.

CONCLUSION: Increasing age and a woman's career are significant risk factors of spontaneous abortion.

The biological properties of venoms of some American coral snakes (Genus micrurus)

Tan NH, Ponnudurai G

Comp. Biochem. Physiol., B, 1992 Mar;101(3):471-4.

PMID: 1582185

1. The biological properties of nine venom samples from six taxa of Micrurus were investigated. The venoms exhibited low protease, phosphodiesterase and 5'-nucleotidase activities, moderate to strong phospholipase A and hyaluronidase activities, variable L-amino acid oxidase activity and were devoid of arginine ester hydrolase and thrombin-like activities. Some venom samples exhibited strong acetylcholinesterase activity. Venoms of M. c. dumerili and M. frontalis exhibited exceptionally high alkaline phosphomonoesterase activity while two of the M. f. fulvius venom samples tested exhibited strong hemorrhagic activity in mice. 2. The polyacrylamide gel electrophoretic patterns of the venoms indicate that most of the Micrurus venom proteins are basic proteins. All Micrurus venoms tested exhibited similar SDS-polyacrylamide gel electrophoretic patterns, with an intense low mol. wt protein band. 3. The Micrurus venoms appear to exhibit biological properties similar to other elapid venoms found in Asia and Africa. There are, however, no common characteristics in the biological properties of the venoms examined at the generic level.

The biological properties of venoms from juvenile and adult taipan (Oxyuranus scutellatus) snakes

Tan NH, Armugam A, Mirtschin PJ

Comp. Biochem. Physiol., B, 1992 Nov;103(3):585-8.

PMID: 1458834

1. The biological properties of four venom pooled samples from adult taipan (Oxyuranus scutellatus) snakes and one pooled venom sample from six juvenile taipan snakes (11 months old) were compared. 2. The intravenous LD50 (median lethal dose), procoagulant activity and enzymatic activities of the juvenile venom were not significantly different from those of the adult venoms. 3. The juvenile and adult venoms exhibited similar polyacrylamide gel electrophoretic (PAGE) and SDS-PAGE patterns, indicating that they possessed a similar protein composition. 4. The results suggest that there is no significant age-dependency in the biological properties of taipan venom.

Comparative study of the enzymatic, hemorrhagic, procoagulant and anticoagulant activities of some animal venoms

Tan NH, Ponnudurai G

Comp Biochem Physiol C Comp Pharmacol Toxicol, 1992 Oct;103(2):299-302.

PMID: 1360387

1. The enzymatic, hemorrhagic, procoagulant and anticoagulant activities of venoms of some animals including snakes, lizards, toads, scorpions, spider, wasps, bees and ants were compared. 2. Snake venom was the richest source of enzymes among the animal venoms. Most other animal venoms were devoid of phosphodiesterase, L-amino acid oxidase, alkaline phosphomonoesterase and acetylcholinesterase activities and only a few exhibited arginine ester hydrolase activity. These venoms, however, exhibited wide ranges of protease, 5'-nucleotidase and hyaluronidase activities. Most of the animal venoms examined exhibited some phospholipase A activity. 3. Other than snake venoms, only venoms of the toad Bufo calamita and the lizards were hemorrhagic, and only venoms of the social wasps, social bees and harvester ant exhibited strong anticoagulant activity. Procoagulant activity occurs only in snake venoms.

A comparative study on the electrophoretic patterns of snake venoms

Tan NH, Ponnudurai G

Comp. Biochem. Physiol., B, 1992 May;102(1):103-9.

PMID: 1526113

1. Examination of the polyacrylamide gel electrophoretic (PAGE) and SDS-PAGE patterns of snake venoms shows that these patterns are useful for species differentiation (and hence identification) for snakes of certain genera but have only limited application for snakes from some other genera, due either to the marked individual variations in the venoms or the lack of marked interspecific differences within the same genus. 2. There is no substantial intersubspecific difference in the electrophoretic patterns of the venoms. 3. In general there are no common characteristics in the electrophoretic patterns of the venom at the generic level because of the wide variations in the electrophoretic patterns of venoms of snakes within the same genus. 4. At the familial level, the venoms of Elapidae exhibited SDS-PAGE patterns distinct from those of Crotalidae.

A comparative study of the biological properties of some sea snake venoms

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.

A comparative study of the biological properties of Dendroaspis (mamba) snake venoms

Tan NH, Arunmozhiarasi A, Ponnudurai G

Comp Biochem Physiol C Comp Pharmacol Toxicol, 1991;99(3):463-6.

PMID: 1685421

1. The biological properties of twelve samples of venoms from all four species of Dendroaspis (mamba) were investigated. 2. Dendroaspis venoms generally exhibited very low levels of protease, phosphodiesterase and alkaline phosphomonoesterase; low to moderately low level of 5'-nucleotidase and very high hyaluronidase activities, but were devoid of L-amino acid oxidase, phospholipase A, acetylcholinesterase and arginine ester hydrolase activities. The unusual feature in venom enzyme content can be used to distinguish Dendroaspis venoms from other snake venoms. 3. All Dendroaspis venoms did not exhibit hemorrhagic or procoagulant activity. Some Dendroaspis venoms, however, exhibited strong anticoagulant activity. The intravenous median lethal dose of the venoms ranged from 0.5 microgram/g mouse to 4.2 micrograms/g mouse. 4. Venom biological activities are not very useful for the differentiation of the Dendroaspis species. The four Dendroaspis venoms, however, can be differentiated by their venom SDS-polyacrylamide gel electrophoretic patterns.

A comparative study of the biological activities of rattlesnake (genera Crotalus and Sistrurus) venoms

Tan NH, Ponnudurai G

Comp Biochem Physiol C Comp Pharmacol Toxicol, 1991;98(2-3):455-61.

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.

Purification and characterization of two acidic phospholipase A2 enzymes from king cobra (Ophiophagus hannah) snake venom

Tan NH, Saifuddin MN

Int. J. Biochem., 1990;22(5):481-7.

PMID: 2347427

1. The two major phospholipase A2 enzymes (OHPLA-DE1 and OHPLA-DE2) of king cobra (Ophiophagus hannah) venom have been purified to electrophoretic homogeneity. 2. The isoelectric points of OHPLA-DE1 and OHPLA-DE2 were 3.81 and 3.89, respectively and the Mws were 14,000 and 15,000, respectively, as estimated by Sephadex G-75 gel filtration chromatography; and 14,000 as estimated by SDS-PAGE. 3. The enzymes were not lethal to mice at a dosage of 10 micrograms/g body wt by i.v. route. Both phospholipase A2 enzymes, however, exhibited moderate edema-inducing and anti-coagulant activities. 4. Bromophenacylation of the enzymes reduced the enzymatic activity drastically but did not affect the edema-inducing activity of the enzymes.

The anticoagulant activity of Malayan cobra (Naja naja sputatrix) venom and venom phospholipase A2 enzymes

Tan NH, Arunmozhiarasi A

Biochem. Int., 1989 Oct;19(4):803-10.

PMID: 2619749

Malayan cobra (Naja naja sputatrix) venom was found to exhibit an in vitro anticoagulant activity that was much stronger than most common cobra (genus Naja) venoms. The most potent anticoagulants of the venom are two lethal phospholipase A2 enzymes with pI's of 6.15 and 6.20, respectively. The anticoagulant activity of the venom is due to the synergistic effect of the venom phospholipase A2 enzymes and polypeptide anticoagulants. Bromophenacylation of the two phospholipase A2 enzymes reduced their enzymatic activity with a concomitant drop in both the lethal and anticoagulant activities.

Isolation and characterization of an unusual form of L-amino acid oxidase from King cobra (Ophiophagus hannah) venom

Tan NH, Saifuddin MN

Biochem. Int., 1989 Oct;19(4):937-44.

PMID: 2619759

The L-amino acid oxidase (EC 1. 4. 3. 2) from King cobra (Ophiophagus hannah) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was determined to be 140000 when examined by gel filtration and 68000 by SDS-polyacrylamide gel electrophoresis. The enzyme had an isoelectric point of 4.5 and an intravenous LD50 of 5 micrograms/g in mice. It is a glycoprotein and contains two moles of FAD per mole of enzyme. The enzyme exhibited unusual thermal stability and unlike most other venom L-amino acid oxidases, it was stable in alkaline solution and was not inactivated by freezing.

Isolation and characterization of an acidic lethal phospholipase Az from Malayan cobra (Naja naja sputatrix) venom

Tan NH, Arunmozhiarasi A

Biochem. Int., 1989 Apr;18(4):785-92.

PMID: 2764979

An acidic, lethal phospholipase Az was purified to electrophoretic homogeneity from the venom of the Malayan cobra (Naja naja sputatrix). The enzyme has an isoelectric point of 5.58, a molecular weight of 12000, and a medium lethal dose (LD50) of 0.86 micrograms/g in mice by intravenous injection. The enzyme also exhibited weak anticoagulant and edema-forming activities. The amino acid composition of the enzyme is similar to those of other cobra venom phospholipases Az.

The edema inducing activity of phospholipase A2 enzymes

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.

A comparative study of the biological properties of some venoms of snakes of the genus Bothrops (American lance-headed viper)

Tan NH, Ponnudurai G

Comp. Biochem. Physiol., B, 1991;100(2):361-5.

PMID: 1799979

1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, alkaline phosphomonoesterase, 5'-nucleotidase, hyaluronidase, arginine ester hydrolase, phospholipase A, L-amino acid oxidase and protease activities of 26 samples of venoms from 13 species of Bothrops were determined, and the Sephadex G-75 gel filtration patterns for some of the venoms also examined. 2. The results show that while there are considerable individual variations in the biological activities of many of the Bothrops venoms tested, there are some common characteristics at the genus and species levels. 3. The differences in the biological properties of the Bothrops venoms tested can be used for the differentiation of most Bothrops species examined.

Substrate specificity of king cobra (Ophiophagus hannah) venom L-amino acid oxidase

Tan NH, Saifuddin MN

Int. J. Biochem., 1991;23(3):323-7.

PMID: 2044840

1. Substrate specificity of purified king cobra (Ophiophagus hannah) venom L-amino acid oxidase was investigated. 2. The enzyme was highly specific for the L-enantiomer of amino acid. Effective oxidation of L-amino acid by the enzyme requires the presence of a free primary alpha-amino group but the alpha-carboxylate group is not as critical for the catalysis. 3. The enzyme was very active against L-Lys, L-Phe, L-Leu, L-Tyr, L-Tryp, L-Arg, L-Met, L-ornithine, L-norleucine and L-norvaline and moderately active against L-His, L-cystine and L-Ileu. Other L-amino acids were oxidized slowly or not oxidized. 4. The data suggest the presence of a side chain binding site in the enzyme, and that the binding site comprises at least five 'subsites': the hydrophobic subsites a, b and c; and the two 'amino' binding subsites d and e. Subsite b appears to be able to accommodate two methylene/methyl carbons.

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