Torano A E, Nakamura S, Levin J
Thromb Res. 1984 Jun 1;34(5):407-17. doi: 10.1016/0049-3848(84)90245-7.
A clotting enzyme, associated with the endotoxin-mediated activation of the cellularly based coagulation system of the American horseshoe crab (Limulus polyphemus), was considerably purified by a modification of the method employed to purify the corresponding enzyme from the Japanese horseshoe crab (Tachypleus tridentatus) (Nakamura, et al., 1982). This enzyme was inhibited by DFP, benzamidine, p-aminobenzamidine, antithrombin III, soybean trypsin inhibitor, and antipain, suggesting that it is a trypsin-type serine protease. The enzyme demonstrated amidolytic activity to Ac-Ile-Glu-Gly-Arg-pNA (S-2423) and related synthetic substrates (S-2222, S-2422, S-2337, and Boc-Leu-Gly-Arg-pNA) but not to other substrates (S-2160, S-2238, S-2251, S-2444, S-2266, and S-2302), indicating specificity similar to mammalian blood coagulation Factor Xa. These properties of the Limulus enzyme were identical with those of the corresponding Tachypleus enzyme. The structure and function of the enzymes in these two species probably have been highly conserved during the past few hundred million years of their evolution.
一种与美国鲎（Limulus polyphemus）基于细胞的凝血系统的内毒素介导激活相关的凝血酶，通过对从日本鲎（Tachypleus tridentatus）中纯化相应酶所采用方法的改进得到了相当程度的纯化（中村等人，1982年）。这种酶受到二异丙基氟磷酸酯（DFP）、苯甲脒、对氨基苯甲脒、抗凝血酶III、大豆胰蛋白酶抑制剂和抑肽酶的抑制，表明它是一种胰蛋白酶型丝氨酸蛋白酶。该酶对乙酰 - 异亮氨酸 - 谷氨酸 - 甘氨酸 - 精氨酸 - 对硝基苯胺（S - 2423）及相关合成底物（S - 2222、S - 2422、S - 2337和叔丁氧羰基 - 亮氨酸 - 甘氨酸 - 精氨酸 - 对硝基苯胺）表现出酰胺水解活性，但对其他底物（S - 2160、S - 2238、S - 2251、S - 2444、S - 2266和S - 2302）没有活性，表明其特异性与哺乳动物凝血因子Xa相似。鲎这种酶的这些特性与相应的日本鲎酶的特性相同。在过去几亿年的进化过程中，这两个物种中酶的结构和功能可能一直高度保守。
