Biochemical & Pharmacological Studies on Polypeptides with Bradykinin Potentiating Activity Isolated from the Venom of the Egyptian Scorpion Buthus Occitanus

In the present years, it has been noticed in the international scientific literatures a rapid increase in the studies of animal venoms and their constituents , only as .research tools for. the neurologists, hematologists. physiologists and pharmacologists but also mainly in the pharmaceutical industry, for the development of potential veterinarian and human drugs. Consequently, this Submitted work was conducted to look for the polypeptides -responsible for the BK potentiating activity in. the venom of the scorpion Buthus occitanus. The sorpions were milked by electric stimulation (6 volts) at the articular membrane of the telson. from 1500 scorpions, about one gram of dry venom was obtained within 4 months. The crude venom was dissolute in distilled water and then centrifuged. The supernatant was collected and dialyzed with spectrapore 3 membrane (cut off M.W. 3500 ) for three days at 4 °C. The dialysate and dialyzed venom were lyophilized and then quanlitated by amino acid analysis , after acid hydrolysis. The dialysate fraction was not toxic for mice at doses up to 100 mg/mouse via intracerebrovenlricular injection. The potentiation of BK on the isolated guinea pig ileum and the rat uterus were the biological models used to follow the BK potentiating activity in each step of purification. BK potentiating activity was found in dialysate separated from the bulk of the venom protein. Six chromatographic fractions (A. to F) from dialysale were isolated by RP-HPLC. Each fraction was collected separatelly, lyophilized and then quantitaled by amino acid composition after acid hydrolysis. Fractions C. and F were found as BK potentiators, With system used, fraction F was more hyDROPhobic as. well as more potent than fraction C. Further RP-HPLC .purification of these fractions was performed. Ten peptides were obtained homogeneous under the conditions used. One peptide (,C2) in fraction C andseven peptides (Fi,F3,F4-2>F5-2.F6.F7 and F8) in fraction F exhibited BK potentiating activity.