Orning L, Stephens R W, Petersen L B, Hamers M J, Stormorken H, Sakariassen K S
Nycomed Imaging AS, Oslo, Norway.
Thromb Res. 1997 Apr 1;86(1):57-67. doi: 10.1016/s0049-3848(97)00045-5.
We have found that synthetic peptides derived from the two epidermal growth factor-like domains of factor VII are inhibitors of tissue factor dependent factor X activation. Inhibition was most pronounced for a constrained sequence of amino acids corresponding to positions 91-102 of factor VII, Cys-Val-Asn-Glu-Asn-Gly-Gly-Cys-Glu-Gin-Tyr-Cys. The biological activity appeared to be localized to the tripeptide 'motif', Glu-Gln-Tyr, within the larger sequence. The cyclic peptide was also an inhibitor of tissue factor induced coagulation of plasma, using lipidated tissue factor or tissue factor expressed on the surface of living cells. However, it did not interfere with intrinsic coagulation. Inhibition of factor X activation was dose-dependent with an IC50 value of 350 microM. Kinetic analyses revealed non-competitive inhibition with respect to factor X and suggested that the peptide sequence interferes with the factor VII/tissue factor/factor X complex formation and function. A pentapeptide analog of the putative pharmacophore was also a dose-dependent inhibitor of factor X activation with an IC50 value of 560 microM, but the tripeptide, Glu-Gin-Tyr, alone was without effect. Our results suggest a direct role for the second epidermal growth factor-like domain of factor VII, and in particular its loop I, in the formation and function of the factor VII/tissue factor/factor X complex.
我们发现，源自因子VII两个表皮生长因子样结构域的合成肽是组织因子依赖性因子X激活的抑制剂。对于对应于因子VII第91 - 102位氨基酸的一段受限氨基酸序列（半胱氨酸-缬氨酸-天冬酰胺-谷氨酸-天冬酰胺-甘氨酸-甘氨酸-半胱氨酸-谷氨酸-谷氨酰胺-酪氨酸-半胱氨酸），抑制作用最为显著。生物活性似乎定位于较大序列中的三肽“基序”，即谷氨酸-谷氨酰胺-酪氨酸。使用脂化组织因子或活细胞表面表达的组织因子时，环肽也是组织因子诱导的血浆凝固的抑制剂。然而，它并不干扰内源性凝血。因子X激活的抑制呈剂量依赖性，IC50值为350微摩尔。动力学分析显示对因子X为非竞争性抑制，并表明该肽序列干扰因子VII/组织因子/因子X复合物的形成和功能。推定药效基团的五肽类似物也是因子X激活的剂量依赖性抑制剂，IC50值为560微摩尔，但单独的三肽谷氨酸-谷氨酰胺-酪氨酸没有作用。我们的数据表明因子VII的第二个表皮生长因子样结构域，特别是其环I，在因子VII/组织因子/因子X复合物的形成和功能中起直接作用。
