Bioactive peptides of European edible frog (Rana esculenta) skin secretion identification, precursor cloning and metabolism

Amphibians have survived successfully between water and land for more than 150 million years, partly based on their highly-evolved, unique and efficient micro-and macro-predator defence systems. Amphibian skin secretions play a major role in survival and they are complex 'bio-cocktails' composed of numerous bioactive molecules including antimicrobial peptides, neuropeptides and protease inhibitors. These various bioactive compounds produced in the amphibian skin secretion not only protect amphibians from pathogen infections and predator attacks but also guarantee the hosts day-to-day survival in complicated environments. More recently, they also provide new insights and new leads in the development of novel human therapeutics. Amphibian skins have been widely used in folk medicines for centuries due to their wide range of pharmacological effects. In modem times, the identification and isolation of potential therapeutic bioactive molecules from amphibian skin secretions has realised that many are excellent templates for drug design. In this study, the skin secretion of the European edible frog, Rana esculenta, was obtained for the purpose of discovering novel bioactive peptides that may have the potential as leads for the design of human therapeutics. The mature active peptides were identified through the application of reverse phase HPLC, mass spectrometry and peptide sequencing. Meanwhile, the precursor sequences of such bioactive peptides were established through construction of a cDNA library from skin secretion followed by application of PCR-based molecular cloning methods. Each identified mature active peptide was chemically-synthesised by solid phase peptide synthesis followed by critical biological characterisation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo