McMullen B A, Fujikawa K, Kisiel W
Department of Biochemistry, University of Washington, Seattle 98195.
Biochemistry. 1989 Jan 24;28(2):674-9. doi: 10.1021/bi00428a039.
The amino acid sequence of a protease, protein C activator, from Agkistrodon contortrix contortrix venom was determined. Peptide fragments obtained by chemical or enzymatic cleavage of the S-carboxymethylated protein were purified by gel filtration and reverse-phase high-performance liquid chromatography. The present study demonstrates that protein C activator from A. contortrix contortrix venom is a trypsin-type serine protease that is composed of 231 residues with a molecular weight of 25,095 for the polypeptide portion of the molecule. By analogy to the mammalian serine proteases, the catalytic triad in venom protein C activator consists of His-40, Asp-85, and Ser-177. The protein also contains three N-linked glycosylation sites at Asn-21, Asn-78, and Asn-129. The amino acid sequence of protein C activator exhibits a high degree of sequence identity with other snake venom proteases: 73% with batroxobin, 68% with flavoxobin, and 55% with Russell's viper venom factor V activator.
已测定了来自铜头蝮蛇毒液的一种蛋白酶——蛋白C激活剂的氨基酸序列。通过对S-羧甲基化蛋白进行化学或酶切得到的肽片段，经凝胶过滤和反相高效液相色谱法进行纯化。本研究表明，来自铜头蝮蛇毒液的蛋白C激活剂是一种胰蛋白酶型丝氨酸蛋白酶，该分子的多肽部分由231个残基组成，分子量为25,095。与哺乳动物丝氨酸蛋白酶类似，毒液蛋白C激活剂中的催化三联体由His-40、Asp-85和Ser-177组成。该蛋白在Asn-21、Asn-78和Asn-129处还含有三个N-连接糖基化位点。蛋白C激活剂的氨基酸序列与其他蛇毒蛋白酶具有高度的序列同一性：与巴曲酶的同一性为73%，与黄曲霉毒素的同一性为68%，与罗素蝰蛇毒因子V激活剂的同一性为55%。
