New proline-rich oligopeptides from the venom of African adders: Insights into the hypotensive effect of the venoms

• Published in: Biochimica et biophysica acta Vol. 1850; no. 6; pp. 1180 - 1187
• Main Authors: Kodama, Roberto T., Cajado-Carvalho, Daniela, Kuniyoshi, Alexandre K., Kitano, Eduardo S., Tashima, Alexandre K., Barna, Barbara F., Takakura, Ana Carolina, Serrano, Solange M.T., Dias-Da-Silva, Wilmar, Tambourgi, Denise V., Portaro, Fernanda V.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2015
• Subjects: Africa; angiotensin I; Angiotensin-converting enzyme (ACE); angiotensin-converting enzyme inhibitors; Angiotensin-Converting Enzyme Inhibitors - chemical synthesis; Angiotensin-Converting Enzyme Inhibitors - isolation & purification; Angiotensin-Converting Enzyme Inhibitors - toxicity; Animals; antihypertensive effect; Arterial Pressure - drug effects; Bitis; Bitis arietans; bradykinin; Bradykinin-potentiating peptide (BPP); Chromatography, High Pressure Liquid; Fluorescence Resonance Energy Transfer; Heart Rate - drug effects; Hypotension; Hypotension - chemically induced; Hypotension - physiopathology; in vitro studies; in vivo studies; Male; mass spectrometry; oligopeptides; Oligopeptides - chemical synthesis; Oligopeptides - isolation & purification; Oligopeptides - toxicity; peptidyl-dipeptidase A; Proline; Proline-rich oligopeptide (PRO); Rats, Wistar; Renin-Angiotensin System - drug effects; snakes; synthetic peptides; tachycardia; Tachycardia - chemically induced; Tachycardia - physiopathology; Tandem Mass Spectrometry; Venom; venoms; Viper Venoms - chemistry; Viper Venoms - toxicity; Africa; Bradykinin-potentiating peptide (BPP); Bitis; Angiotensin-converting enzyme (ACE); Venom; Hypotension; Proline-rich oligopeptide (PRO)
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2015.02.005

The snakes from the Bitis genus are some of the most medically important venomous snakes in sub Saharan Africa, however little is known about the composition and effects of these snake venom peptides. Considering that the victims with Bitis genus snakes have exacerbate hypotension and cardiovascular disorders, we investigated here the presence of angiotensin-converting enzyme modulators on four different species of venoms. The peptide fractions from Bitis gabonica gabonica, Bitis nasicornis, Bitis gabonica rhinoceros and Bitis arietans which showed inhibitory activity on angiotensin-converting enzyme were subjected to mass spectrometry analysis. Eight proline-rich peptides were synthetized and their potencies were evaluated in vitro and in vivo. The MS analysis resulted in over 150 sequences, out of which 32 are new proline-rich oligopeptides, and eight were selected for syntheses. For some peptides, inhibition assays showed inhibitory potentials of cleavage of angiotensin I ten times greater when compared to bradykinin. In vivo tests showed that all peptides decreased mean arterial pressure, followed by tachycardia in 6 out of 8 of the tests. We describe here some new and already known proline-rich peptides, also known as bradykinin-potentiating peptides. Four synthetic peptides indicated a preferential inhibition of angiotensin-converting enzyme C-domain. In vivo studies show that the proline-rich oligopeptides are hypotensive molecules. Although proline-rich oligopeptides are known molecules, we present here 32 new sequences that are inhibitors of the angiotensin-converting enzyme and consistent with the symptoms of the victims of Bitis spp, who display severe hypotension. •More than 150 peptides were sequenced from four Bitis spp venoms.•34 of these sequences are proline rich oligopeptides.•Eight proline rich oligopeptides were synthesized for in vitro and in vivo assays.•In vitro assays indicated that six out of eight were ACE inhibitors.•All eight peptides induced hypotension but only six of them also induced bradycardia.