QUB-1951: a bioactive peptide from the skin secretion of the Chinese piebald Odorous frog, Odorrana schmackeri
Peptides derived from the secretion of various frogs and toads show a great diversity and potential for discovery and development of novel therapeutics. In recent years, peptide-based drugs have been in the spotlight due to their high therapeutic potential combining high efficacy with low toxicity. In this research, a bioactive peptide was obtained from the skin secretion of the Chinese piebald odorous frog (Odorrana schmackeri). The precursor encoded cDNA was identified by using “shotgun” cloning, with the amino acid sequence of putative mature peptide, AVNIPFKVHFRCKAAFC. In order to obtain sufficient peptides to carry out the bioactive assays, solid phase peptide synthesis (SPPS) was used to synthesize. The molecular weight was confirmed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and purified by reverse phase-high performance liquid chromatography (RP-HPLC). This synthetic peptide was then subjected to functional assays, including antimicrobial assay, trypsin inhibition assay haemolysis assay, and cell viability assay. The results showed that this peptide had the ability to inhibit trypsin with Ki value of 1.97 μM, but neither antimicrobial nor severe haemolytic activity were detected. It was the first time to report a novel kunitz inhibitor peptide discovered from the frog secretion, which provides new insight of unique trypsin inhibitors from natural products.
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