Abstract
A novel naturally-occurring bradykinin-related peptide (BRP) with an N-terminal extension, named RVA-Thr6-Bradykinin (RVA-Thr6-BK), was here isolated and identified from the cutaneous secretion of Odorrana hejiangensis (O. hejiangensis). Thereafter, in order to evaluate the difference in myotropic actions, a leucine site-substitution variant from Amolops wuyiensis skin secretion, RVA-Leu1, Thr6-BK, was chemically synthesized. Myotropic studies indicated that single-site arginine (R) replacement by leucine (L) at position-4 from the N-terminus, altered the action of RVA-Thr6-BK from an agonist to an antagonist of BK actions on rat ileum smooth muscle. Additionally, both BK N-terminal extended derivatives (RVA-Thr6-BK and RVA-Leu1, Thr6-BK) exerted identical myotropic actions to BK, such as increasing the frequency of contraction, contracting and relaxing the rat uterus, bladder and artery preparations, respectively.
Highlights
Bradykinin (BK) is ubiquitous in mammals and its generation from precursor kininogens by plasma/tissue kallikreins in the human kallikrein-kinin system (KKS), has been well-researched [1,2,3].Currently, BK has been proved to be a critical participant associated with human physiological and pathological processes, such as adjusting the functions of the cardiovascular, renal and nervous systems, smooth muscle contraction, glucose metabolism, cell proliferation, inflammation and the production of pain [3,4]
A full-length biosynthetic bradykinin-related peptide (BRP)-precursor cDNA was consistently cloned from the cDNA library constructed from the skin secretion of O. hejiangensis (Figure 1)
The results indicated that concentration of BRPs giving the half-maximal response respectively
Summary
Bradykinin (BK) is ubiquitous in mammals and its generation from precursor kininogens by plasma/tissue kallikreins in the human kallikrein-kinin system (KKS), has been well-researched [1,2,3]. BK has been proved to be a critical participant associated with human physiological and pathological processes, such as adjusting the functions of the cardiovascular, renal and nervous systems, smooth muscle contraction, glucose metabolism, cell proliferation, inflammation and the production of pain [3,4]. Following the initial discovery mammalian BK from Rana temporaria in 1965, numerous identical BK and its structural analogues with potent smooth muscle stimulant have been found in anuran amphibian venom apparatus-skin [7,8,9,10,11,12]. An extraordinary structural diversity was observed in anuran skin bradykinin-related peptides (BRPs). In addition to Toxins 2019, 11, 376; doi:10.3390/toxins11070376 www.mdpi.com/journal/toxins
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