Toxins from Venomous Animals: Gene Cloning, Protein Expression and Biotechnological Applications

Abstract

Venoms are the secretion of venomous animals, which are synthesized and stored in specific areas of their body i.e., venom glands. The animals use venoms for defense and/or to immo‐ bilize their prey. Most of the venoms are complex mixture of biologically active compounds of different chemical nature such as multidomain proteins, peptides, enzymes, nucleotides, lipids, biogenic amines and other unknown substances. Venomous animals as snakes, spi‐ ders, scorpions, caterpillars, bees, insects, wasps, centipedes, ants, toads and frogs have largely shown biotechnological or pharmacological applications. During long-term evolu‐ tion, venom composition underwent continuous improvement and adjustment for efficient functioning in the killing or paralyzing of prey and/or as a defense against aggressors or predators. Different venom components act synergistically, thus providing efficiency of ac‐ tion of the components. Venom composition is highly species-specific and depends on many factors including age, sex, nutrition and different geographic regions. Toxins, occurring in venoms and poisons of venomous animals, are chemically pure toxic molecules with more or less specific actions on biological systems [1-3]. A large number of toxins have been isolat‐ ed and characterized from snake venoms and snake venoms repertoire typically contain from 30 to over 100 protein toxins. Some of these molecules present enzymatic activities, whereas several others are non-enzymatic proteins and polypeptides. The most frequent en‐ zymes in snake venoms are phospholipases A2, serine proteinases, metalloproteinases, ace‐ tylcholinesterases, L-amino acid oxidases, nucleotidases and hyaluronidases. Higher catalytic efficiency, heat stability and resistance to proteolysis as well as abundance of snake venom enzymes provide them attractive models for biotechnologists, pharmacologists and biochemists [3-4]. Scorpion toxins are classified according to their structure, mode of action,