Yamakawa Y, Omori-Satoh T, Mebs D
Department of Biochemistry and Cell Biology, National Institute of Health, Tokyo, Japan.
Biochim Biophys Acta. 1995 Feb 22;1247(1):17-23. doi: 10.1016/0167-4838(94)00171-c.
The optimal pH of the proteinase activity of hemorrhagins, BHRa and BHRb, isolated from the venom of Bitis arietans (puff adder) is pH 9. The activity was inhibited by metal chelating agents such as EDTA, 1,10-phenanthroline and 8-hydroxyquinoline, but not by phenylmethanesulfonyl fluoride and soybean trypsin inhibitor, suggesting that they are metalloproteinases. The hemorrhagins hydrolyzed all gelatin preparations derived from types I, II, III and IV collagen. On the other hand, only type IV native collagen was hydrolyzed. Gel electrophoretic profiles of type IV collagen hydrolysates suggested that the hemorrhagins affect the collagen helical chains at different cleavage sites. The hemorrhagins hydrolyzed several synthetic peptides such as angiotensin I and luteinizing hormone-releasing hormone, but not synthetic substrates for bacterial and animal collagenases. The hydrolysis of various peptides indicated that the hemorrhagins are endopeptidases. The insulin B chain is cleaved by BHRa and BHRb at 11 and 10 positions, respectively. The substrate specificity of the hemorrhagins was compared with those of known hemorrhagic and nonhemorrhagic venom proteinases.
从鼓腹咝蝰（Bitis arietans）毒液中分离出的出血毒素BHRa和BHRb的蛋白酶活性的最适pH值为9。该活性受到金属螯合剂如EDTA、1,10 - 菲咯啉和8 - 羟基喹啉的抑制，但不受苯甲基磺酰氟和大豆胰蛋白酶抑制剂的抑制，这表明它们是金属蛋白酶。出血毒素能水解所有来源于I型、II型、III型和IV型胶原的明胶制剂。另一方面，仅天然IV型胶原被水解。IV型胶原水解产物的凝胶电泳图谱表明，出血毒素在不同的切割位点影响胶原螺旋链。出血毒素能水解几种合成肽，如血管紧张素I和促黄体激素释放激素，但不能水解细菌和动物胶原酶的合成底物。各种肽的水解表明出血毒素是内肽酶。胰岛素B链分别被BHRa和BHRb在第11位和第10位切割。将出血毒素的底物特异性与已知的出血性和非出血性毒液蛋白酶的底物特异性进行了比较。
