QUB-1073: a bioactive peptide from the skin secretion of Phyllomedusa rohdei

  • Zhaoxin Tian

Student thesis: Masters ThesisMasters

Abstract

This study aimed to examine the characteristics of a bioactive peptide (QUB-1073) from the skin secretion of Phllomedusa rohdei and to determine the pharmacological activity on rat uterus and urinary bladder smooth muscle.
A variety of biologically active peptides, including some new antimicrobial peptides and neuropeptides, have been extracted from the secretions of frog skins. Due to the abundant bioactive peptides and other compounds, the study of amphibian skin secretions has gradually become a hot spot for the development of new peptide drugs. However, amphibian skin secretions have been used as medicine for a long time in China, South America and other areas.
The peptide reported in this paper has the following primary structure, Glp-Leu-Trp-Ala-Thr-Gly-His-Phe-Met-NH2, which was deduced by shotgun cloning from cloned skin precursor-encoding cDNA and was previously reported in 1985. The peptide was synthesised by solid phase peptide synthesis (SPPS) and purified by Reverse-phase High-Performance Liquid Chromatography (HPLC) for assessments of its bioactive functions. These assays showed that QUB-1073 might have no haemolytic and antimicrobial functions but had strong rat uterus and bladder smooth muscle contractive activities. It had EC50 (half maximal effective concentration) values of 11 nM and 44 nM, respectively, indicating that it is a potent agonist of smooth muscle contraction which may have potential therapeutic applications of bladder disorder and sexual dysfunction. Through bioinformatic tool Protein Blast it was established that the peptide had a similar sequence to several bombesin-like peptides which all had agonistic function on the neuromedin B (NMB) receptor (BB1).
In conclusion, this study assessed QUB-1073 for several biological actions and found it to be potently myotropic. Considering sequence of peptide QUB-1073, it is most likely an agonist of the BB1 receptor.
Date of AwardJul 2018
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorLei Wang (Supervisor), Tianbao Chen (Supervisor), Chris Shaw (Supervisor) & Mei Zhou (Supervisor)

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