Gaspar A R, Joubert A M, Crause J C, Neitz A W
Department of Biochemistry, University of Pretoria, South Africa.
Exp Appl Acarol. 1996 Oct;20(10):583-98. doi: 10.1007/BF00052809.
An inhibitor of activated coagulation factor X (fXa) was isolated from salivary gland extracts prepared from Ornithodoros savignyi using a two-step procedure, involving reversed-phase high-performance liquid chromatography (RP-HPLC) and diethylaminoethyl (DEAE) ion-exchange chromatography. From its behaviour during DEAE chromatography it could be deduced that it possesses an acidic pI (approximately 4.6). Capillary zone electrophoresis (CZE) of the purified inhibitor showed it to be homogeneous. The molecular mass was determined as 12 kDa using capillary gel electrophoresis (CGE) and as 7183.4 using laser desorption mass spectrometry (LDMS). The N-terminal amino acid sequence (residues 1-12) was determined and found to share a 66% identity with tick anticoagulant peptide (TAP). The O. savignyi peptide is a slow, tight-binding inhibitor of fXa (Ki = 0.83 +/- 0.10 nM). The interaction of the fXa--inhibitor was found to be competitive and dependent on ionic strength. Preliminary investigations show that the inhibitor may be specific for fXa.
采用两步法从萨氏钝缘蜱唾液腺提取物中分离出活化凝血因子X（fXa）抑制剂，该两步法包括反相高效液相色谱（RP-HPLC）和二乙氨基乙基（DEAE）离子交换色谱。从其在DEAE色谱中的行为可以推断，它具有酸性pI（约4.6）。纯化抑制剂的毛细管区带电泳（CZE）显示其具有均一性。使用毛细管凝胶电泳（CGE）测定分子量为12 kDa，使用激光解吸质谱（LDMS）测定为7183.4。测定了N端氨基酸序列（第1至12位残基），发现其与蜱抗凝肽（TAP）有66%的同源性。萨氏钝缘蜱肽是一种对fXa作用缓慢、结合紧密的抑制剂（Ki = 0.83 +/- 0.10 nM）。发现fXa与抑制剂的相互作用具有竞争性且依赖于离子强度。初步研究表明该抑制剂可能对fXa具有特异性。
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