Meki A R, Nassar A Y, Rochat H
Department of Biochemistry, Faculty of Medicine, University of Assiut, Egypt.
Peptides. 1995;16(8):1359-65. doi: 10.1016/0196-9781(95)02036-5.
A nontoxic peptide with bradykinin-potentiating activity was isolated from the dialyzed venom of the scorpion Buthus occitanus by reverse-phase high performance liquid chromatography (RP-HPLC). The pharmacological activity of the peptide was bioassayed by its ability to potentiate added bradykinin (BK) on the isolated guinea pig ileum as well as the isolated rat uterus for contraction. Moreover, the peptide potentiates in vivo the depressor effect of BK on arterial blood pressure in the normotensive anesthetized rat. Chemical characterization of the peptide was also performed. The amino acid composition of the peptide showed 21 amino acid residues per molecule including three proline residues. The amino acid sequence of the purified peptide was confirmed by mass spectrometry. Either N- or C-terminal ends were free. The sequence does not show a homology with bradykinin-potentiating peptides isolated from either scorpion or snake venoms. Furthermore, we did not find a significant sequence homology between the sequence of the isolated peptide and any of proteins or peptides in GenPro or NBRF data banks. The peptide also inhibited angiotensin-converting enzyme (ACE), and could not serve as substrate for the enzyme. It could be concluded that the mechanism of bradykinin-potentiating peptide (BPP) activity may be due to ACE inhibition.
通过反相高效液相色谱法（RP-HPLC）从蝎子奥氏钳蝎的透析毒液中分离出一种具有缓激肽增强活性的无毒肽。该肽的药理活性通过其增强添加的缓激肽（BK）对离体豚鼠回肠以及离体大鼠子宫收缩的能力进行生物测定。此外，该肽在体内增强了BK对正常血压麻醉大鼠动脉血压的降压作用。还对该肽进行了化学表征。该肽的氨基酸组成显示每个分子有21个氨基酸残基，包括三个脯氨酸残基。通过质谱法确认了纯化肽的氨基酸序列。N端或C端均为游离状态。该序列与从蝎子或蛇毒中分离出的缓激肽增强肽没有同源性。此外，我们在GenPro或NBRF数据库中未发现分离肽的序列与任何蛋白质或肽之间存在显著的序列同源性。该肽还抑制血管紧张素转换酶（ACE），并且不能作为该酶的底物。可以得出结论，缓激肽增强肽（BPP）活性的机制可能是由于ACE抑制。
