Jacobs J W, Cupp E W, Sardana M, Friedman P A
Department of Biological Chemistry, Merck Sharp & Dohme Research Laboratories, West Point, PA.
Thromb Haemost. 1990 Oct 22;64(2):235-8.
We have discovered and characterized a novel coagulation factor Xa inhibitor from the salivary gland of the black fly, Simulium vittatum. Salivary glands were surgically dissected from the flies and a crude salivary gland extract was tested for inhibition of a number of coagulation assays. The gland extract inhibited both thrombin and factor Xa. To purify further the factor Xa inhibitor, a factor Xa affinity column was utilized. Final purification of the black fly factor Xa inhibitor was achieved by reverse-phase C8 microbore high pressure liquid chromatography. Inhibition of factor Xa was nearly stoichiometric by the purified inhibitor with no inhibitor of thrombin detected. SDS-polyacrylamide gel electrophoresis indicated the inhibitor had a molecular weight of 18,000 and sequence analysis of the inhibitor revealed a blocked amino terminus. These data indicate that the blood-sucking black fly has evolved a highly potent inhibitor of mammalian coagulation factor Xa to disrupt its host normal hemostatic clotting mechanisms.
我们从黑蝇（Simulium vittatum）的唾液腺中发现并鉴定了一种新型凝血因子Xa抑制剂。通过手术从黑蝇身上解剖出唾液腺，并对粗制唾液腺提取物进行了多种凝血试验的抑制测试。该腺体提取物对凝血酶和因子Xa均有抑制作用。为了进一步纯化因子Xa抑制剂，使用了因子Xa亲和柱。通过反相C8微孔高压液相色谱法实现了黑蝇因子Xa抑制剂的最终纯化。纯化后的抑制剂对因子Xa的抑制作用几乎是化学计量的，未检测到凝血酶抑制剂。SDS-聚丙烯酰胺凝胶电泳表明该抑制剂的分子量为18,000，对该抑制剂的序列分析显示其氨基末端被封闭。这些数据表明，吸血黑蝇已经进化出一种高效的哺乳动物凝血因子Xa抑制剂，以破坏其宿主正常的止血凝血机制。
