QUB-1383, a novel bioactive peptide from the defensive skin secretion of the edible frog (Pelophylax kl. esculentus)

  • Mengru Sang

Student thesis: Masters ThesisMaster of Philosophy


In this study, a novel peptide named QUB-1383 was successfully isolated from the skin secretion of the edible frog (Pelophylax kl. esculentus) via “shotgun” cloning of the precursor-encoding cDNA. Afterwards, the predicted mature peptide was chemically synthesised by solid-phase peptide synthesis and its structure confirmed via MALDI-TOF mass spectrometry. Then the crude synthesised peptide was purified via RP-HPLC. Several bioassays including antimicrobial assays, haemolytic assays and trypsin inhibitor assays were conducted to ascertain its bioactivities. The synthetic QUB-1383 not only possessed potent antimicrobial activity against C.albicans, S. aureus and E. coli with minimal inhibitory concentrations at 4 μM, 2 μM and 16 μM, respectively. However, it also displayed relatively strong haemolytic activity with EC50 value at 39.64 μM. QUB-1383 also exerted weak inhibitory effect to trypsin, with a Ki value of 20.74 ± 6.87 μM.
Due to the potent antimicrobial activity of QUB-1383, this peptide could be considered as a candidate of novel antibiotics after target-modification to minimise its haemolytic effect. Since the working concentration of QUB-1383 to inhibit trypsin was too high, the trypsin inhibitory activity could not be considered for further development.
Date of AwardJul 2017
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorTianbao Chen (Supervisor), Lei Wang (Supervisor), Xinping Xi (Supervisor) & Chengbang Ma (Supervisor)

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