Terada S, Hori J, Fujimura S, Kimoto E
Department of Chemistry, Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka, 814-0180, Japan.
J Biochem. 1999 Jan;125(1):64-9. doi: 10.1093/oxfordjournals.jbchem.a022269.
A non-hemorrhagic proteinase, brevilysin L6 (L6), has been purified to homogeneity from Agkistrodon halys brevicaudus venom by gel filtration and DEAE-Toyopearl 650M chromatography. It is an acidic protein with an isoelectric point of 4.8, and its molecular mass was estimated to be 21.5 kDa by SDS-PAGE. The optimum pH of L6 was about 9. EDTA and o-phenanthroline inhibited the proteolytic activity, suggesting that L6 is a metalloprotease. Cysteine also inhibited the activity of L6, but glutathione did not. The protein was stable in the pH range of 5-8.5 and below 40 degreesC. Calcium ions had no effect on the proteolytic activity of L6 or on its thermal stability. The enzyme preferentially cleaved X-Leu, X-Phe, X-Val, and X-His bonds. L6 showed weak alpha-fibrinogenase activity. The complete amino acid sequence of L6 was also determined by manual Edman degradation. L6 is a non-glycosylated single-chain polypeptide consisting of 203 residues with an N-terminal pyroglutamic acid and a calculated molecular weight of 22,713 Da. Its entire sequence is highly homologous to those of other metalloproteases from various snake venoms. A zinc-binding motif, HEXXHXXGXXH, is located at residues 143-153 in the sequence of L6.
一种非出血性蛋白酶——短蝮蛇溶血素L6（L6），已通过凝胶过滤和DEAE - Toyopearl 650M色谱法从短尾蝮蛇毒中纯化至同质。它是一种酸性蛋白，等电点为4.8，通过SDS - PAGE估计其分子量为21.5 kDa。L6的最适pH约为9。EDTA和邻菲罗啉抑制其蛋白水解活性，表明L6是一种金属蛋白酶。半胱氨酸也抑制L6的活性，但谷胱甘肽没有。该蛋白在pH值5 - 8.5和40℃以下稳定。钙离子对L6的蛋白水解活性及其热稳定性均无影响。该酶优先切割X - Leu、X - Phe、X - Val和X - His键。L6表现出较弱的α - 纤维蛋白原酶活性。L6的完整氨基酸序列也通过手动Edman降解法确定。L6是一种非糖基化的单链多肽，由203个残基组成，N端为焦谷氨酸，计算分子量为22,713 Da。其整个序列与来自各种蛇毒的其他金属蛋白酶高度同源。一个锌结合基序HEXXHXXGXXH位于L6序列的143 - 153位残基处。
