Kimura S, Aoki N
J Biol Chem. 1986 Nov 25;261(33):15591-5.
A plasma proteinase inhibitor, alpha 2-plasmin inhibitor (alpha 2PI), is cross-linked with alpha chain of fibrin(ogen) by activated coagulation Factor XIII (plasma transglutaminase). alpha 2PI serves only as a glutamine substrate (amine acceptor) for activated Factor XIII in the cross-linking reaction, and the cross-linking occurs between Gln-2 of the alpha 2PI molecule and a lysine residue (amine donor) of fibrin(ogen) alpha chain, whose position was investigated. alpha 2PI and fibrinogen were reacted by activated Factor XIII. The resulting alpha 2PI fibrinogen A alpha chain complex was separated and subjected to two cycles of Edman degradation using phenyl isothiocyanate for the first cycle and dimethylaminoazobenzene-isothiocyanate for the second cycle. The aqueous phase after the cleavage stage of the second cycle, containing dimethylaminoazobenzene-thiohydantoin-Gln cross-linked with A alpha chain, was subjected to CNBr fragmentation and tryptic digestion. Only one of the peptides was found to have the peak of absorbance at 420 nm, indicating the presence of dimethylaminoazobenzene-thiohydantoin-Gln in that peptide. The peptide was identified as corresponding to residues Asn-290-Arg-348 of A alpha chain by analyses of the NH2-terminal amino acid sequence and amino acid composition. The peptide contains a single lysine at position 303, indicating that Lys-303 of fibrinogen A alpha chain is the lysine residue that forms a cross-link with Gln-2 of alpha 2PI.
一种血浆蛋白酶抑制剂，α2-纤溶酶抑制剂（α2PI），通过活化的凝血因子 XIII（血浆转谷氨酰胺酶）与纤维蛋白（原）的α链交联。在交联反应中，α2PI仅作为活化因子 XIII 的谷氨酰胺底物（胺受体），交联发生在α2PI分子的Gln-2与纤维蛋白（原）α链的赖氨酸残基（胺供体）之间，对其位置进行了研究。α2PI和纤维蛋白原与活化的因子 XIII 反应。将所得的α2PI-纤维蛋白原Aα链复合物分离，并使用异硫氰酸苯酯进行第一轮埃德曼降解，使用异硫氰酸二甲氨基偶氮苯进行第二轮埃德曼降解，进行两个循环。第二轮裂解阶段后的水相，含有与Aα链交联的二甲基氨基偶氮苯-硫代乙内酰脲-Gln，进行溴化氰裂解和胰蛋白酶消化。仅发现其中一个肽在420nm处有吸光度峰值，表明该肽中存在二甲基氨基偶氮苯-硫代乙内酰脲-Gln。通过对NH2-末端氨基酸序列和氨基酸组成的分析鉴定该肽对应于Aα链的Asn-290-Arg-348残基。该肽在位置303处含有一个赖氨酸，表明纤维蛋白原Aα链的Lys-303是与α2PI的Gln-2形成交联的赖氨酸残基。
