ISOLATION - ANALYSIS AND PROPERTIES OF 3 BRADYKININ-POTENTIATING PEPTIDES (BPP-II, BPP-III, AND BPP-V) FROM BOTHROPS NEUWIEDI VENOM

In the course of systematic investigations on low-molecular-weight com pounds from the venom of Crotalidae and Viperidae, we have isolated an d characterized at least three bradykinin-potentiating peptides (BPP-I I, BPP-III, and BPP-V) from Bothrops neuwiedi venom by gel filtration on Sephadex G-25 M, Sephadex G-10 followed by HPLC. The peptides showe d bradykinin-potentiating action on isolated guinea-pig ileum, for whi ch the BPP-V was more active than of BPP-II, and BPP-III, rat arterial blood pressure, and a relevant angiotensin-converting enzyme (ACE) co mpetitive inhibiting activity. The kinetic studies showed a K-i of the order of 9.7 x 10(-3) mu M to BPP-II, 7 x 10(-3) mu M to BPP-III, and 3.3 x 10(-3) mu M to BPP-V. The amino acid sequence of the BPP-III ha s been determined to be u-Gly-Gly-Trp-Pro-Arg-Pro-Gly-Pro-Glu-Ile-Pro- Pro, and the amino acid compositions of the BPP-II and BPP-V by amino acid analysis were 2Glu-2Gly-1Arg-4Pro-1Ile and 2Glu-2Gly-1Ser-3Pro-2V al-Ille, with molecular weight of 1372, 1046, and 1078, respectively.