antibacterial peptide, phospholipase a2, snake venoms, therapeutic peptides, viper, viperidae
C Paulchamy. Pharmacological perspectives of snake venoms from Viperidae family. The Internet Journal of Pharmacology. 2009 Volume 8 Number 2.
Snake venom is a combination of many different proteins and enzymes. Many of these proteins are harmless to humans, but some are toxins. Snake venoms effects include pro- and anti-blood coagulation, neurotoxicity, mycotoxicity, nephrotoxicity, cardiotoxicity and necrotoxicity. This article has focused only on the principle components of
Everyone assumes the snakes are more dangerous and threat to human society, but many of us have not been known that snakes have possessed a novel factory for human valuable medicines in their venoms. Snake venom contains a variety of chemicals including pharmacological properties. Snake venom is a mixture of different enzymes and having toxic and non-toxic activities. The mechanism of toxin secretion is highly conserved and diversification of matured toxin sequences shows existence of multiple protein isoforms in the venoms to adapt within prey environment1. The action of venom is the combined effect of all components present in the venoms and the snakes escape the effect of own toxins due to specific resistance mechanism and modulation of acetyl choline receptors. Through the recent development of technological knowledge in biotechnology and bioinformatics, snake venoms are widely used to develop anti-venom vaccines and medicine for rescuing snake venoms poisoning patients.
Snakes are taxonomically classified under phylum reptiles of vertebrates in animal kingdom.
Geographic variations in snake venom toxicity
Toxin obtained from a given species may also differ depending on geographical regions. Snake venoms, for example, toxicity of South India would be different from snake venoms in North India. Variation in snake venom composition is a ubiquitous phenomenon at all taxonomic level3. Many factors including phylogeny, geographic origin, season, age and prey preference may influence venom composition. The composition of snake venom is also strongly influenced by environmental factors including habitat, climate and preys4. Sex-based differences in the venom proteome of sibling snakes (
Classification of snake venoms
Snake venom proteins and polypeptides are classified into superfamilies of enzymes and non-enzymatic proteins. The members of each superfamily show similarity in their primary, secondary and tertiary structures, however, their biological functions are distinct still now. Among non-enzymatic proteins, superfamilies of three-finger toxins, serine proteinase inhibitors, C-type lectin-related proteins, atrial natriuretic peptides and nerve growth factors have already been well characterized6-8. L-Amino acid oxidase, phospholipase A2, metalloprotease and ribonuclease A are some examples of superfamilies of enzymes in this family9-13. Based on the structure, activity and components, crude venoms are also classified into cardiotoxin, neurotoxin, cytotoxin and myotoxin4, 14-15.
Snake venoms and drug discovery
The snake venom proteins are of biological interest because of their diverse and selective pharmacological and physiological effects through their interaction with various molecular targets. These proteins are prototypes for: (i) therapeutic agents (ii) pharmacological probes for the diagnosis of several diseases and (iii) research tools to decipher physiological and pathological processes16. Captopril, an antihypertensive drug, is a classic example that was designed based on the peptide inhibitor of angiotensin-converting enzyme from
Snake venoms and pharmacological perspectives
Cardiotoxin forms a major toxic protein found in cobra venom and made up of 60-63 amino acid residues in a single polypeptide chain cross linked by four disulfide bonds. The mechanism of action of cardiotoxin peptide for inducing muscle contractions by
Warprin family proteins
Waprins is a second major family of venom proteins that shows structural similarity to WAPs (whey acidic proteins)22. The WAP domain inhibits Na+-K+ ATPase23, elafin and SLPI (secretory leucocyte proteinase inhibitor), which are proteinase inhibitors with potent antimicrobial activity24-25, ps20 with growth-inhibitory activity26, and SWAM1 and SWAM2 (single WAP motif proteins 1 and 2), which are antibacterial proteins27. Many of the reported WAP domain proteins are involved in the innate immune system. The three-dimensional structure of nawaprin, the first WAP domain protein from snake venom, shows significant similarity to that of elafin, with a flat disc-like shape, characterized by a spiral backbone configuration that forms outer and inner circular segments22. The biological function(s) of nawaprin has yet to be identified. A new member of waprin family, omwaprin from the venom of inland taipan snake (
Platelet aggregation factors
C-type lectin-like protein
A C-type lectin-like protein (CLP), agkisacutacin isolated from
A novel phospholipase A2 (PLA2) from the snake venom of
The venom of Viperdae is a rich source of metalloproteinases, which have potential clinical applications for lowering plasma fibrinogen or dissolving thrombi. Recently, a novel proteinase from
L-Amino acid oxidase
Zn containing metallo-protease, apoptotic pathway inducing L-amino acid oxidase and hydrogen peroxides are identified and evaluated for their respective pharmacological perspectives. Antibacterial activity is found in snake venoms that may be due to L-amino acid oxidase. Antifungal and antiviral activities have also investigated in snake venom of
Though lethal toxin, nuclease, phasphodiesterase, cytotoxin, cardiotoxin and ribonuclease have been isolated and purified from cobra venoms, a little attempt have been made on the venoms of