Kimura S, Tamaki T, Aoki N
Blood. 1985 Jul;66(1):157-60.
When blood plasma containing the NH2-terminal 12-residue peptide (N-peptide) of alpha 2-plasmin inhibitor (alpha 2PI; alpha 2-antiplasmin) was clotted in the presence of calcium ions, the N-peptide and alpha 2PI were cross-linked to fibrin by activated coagulation factor XIII. The amount of N-peptide cross-linked to fibrin was proportional to the concentration of N-peptide present in plasma. On the other hand, the amount of alpha 2PI cross-linked to fibrin was decreased by the presence of N-peptide, and the decrease was in reverse relationship to the increase of cross-linking of N-peptide. Spontaneous fibrinolysis or fibrinolysis induced by tissue plasminogen activator was accelerated by the presence of N-peptide, and the acceleration was dependent on the concentrations of N-peptide and directly proportional to inhibition of alpha 2PI cross-linking exerted by N-peptide. The acceleration was more pronounced when the clot was compacted by platelet-mediated clot retraction or by a squeeze. Fibrinolysis of an alpha 2PI-deficient or a factor XIII-deficient plasma clot was not accelerated by N-peptide. These findings were substantiated in a purified system and support the previous proposal that alpha 2PI is cross-linked to fibrin at the glutamine residue that is next to the NH2-terminus of alpha 2PI, and this factor XIII-mediated cross-linking of alpha 2PI is significant in inhibition of physiologically occurring endogenous fibrinolysis.
当含有α2 - 纤溶酶抑制剂（α2PI；α2 - 抗纤溶酶）NH2末端12个残基肽（N - 肽）的血浆在钙离子存在下发生凝固时，N - 肽和α2PI通过活化的凝血因子XIII与纤维蛋白交联。与纤维蛋白交联的N - 肽量与血浆中存在的N - 肽浓度成正比。另一方面，N - 肽的存在会降低与纤维蛋白交联的α2PI量，且这种降低与N - 肽交联增加呈反比关系。N - 肽的存在会加速自发纤溶或组织型纤溶酶原激活剂诱导的纤溶，且这种加速取决于N - 肽的浓度，并与N - 肽对α2PI交联的抑制直接成正比。当凝块通过血小板介导的凝块回缩或挤压而压实后，纤溶加速更为明显。N - 肽不会加速α2PI缺乏或因子XIII缺乏的血浆凝块的纤溶。这些发现在纯化系统中得到证实，并支持先前的提议，即α2PI在α2PI NH2末端旁边的谷氨酰胺残基处与纤维蛋白交联，并且这种因子XIII介导的α2PI交联在抑制生理发生的内源性纤溶中具有重要意义。
