Lotter H, Timpl R
Eur J Biochem. 1975 Dec 1;60(1):221-6. doi: 10.1111/j.1432-1033.1975.tb20994.x.
The antigenic properties of the cyanogen bromide peptide F-CB3 from bovine fibrinogen alpha-chain were studied in radioimmune assays with rabbit antibodies to fibrinogen or to peptide F-CB3. Both fibrinogen and peptide F-CB3 were indistinguishable in inhibition and dissociation tests. Modification of the single disulfide bridge in peptide F-CB3 either by reduction or by cleavage with cyanide was not accompanied by loss of serologic activity. Inhibition studies with three individual fragments obtained after cyanide cleavage (molecular weight range 7000 to 23000) indicated the presence of at least three distinct antigenic determinants in peptide F-CB3. After trypsin digestion of peptide F-CB3 still 75% of its maximal inhibiting capacity was retained. Lack of change in antigenic activity of peptide F-CB3 after release from the fibrinogen molecule by cyanogen bromide and upon further fragmentation is presumably due to the presence of several sequential antigenic determinants but the presence of conformational determinants could not be entirely excluded. Since no cross-reaction was observed between bovine and human peptides F-B3 one may expect considerable variation in their amino acid sequence.
利用针对纤维蛋白原或肽F-CB3的兔抗体，通过放射免疫测定法研究了来自牛纤维蛋白原α链的溴化氰肽F-CB3的抗原特性。在抑制和解离试验中，纤维蛋白原和肽F-CB3无法区分。肽F-CB3中的单个二硫键无论是通过还原还是用氰化物裂解进行修饰，其血清学活性都不会丧失。对氰化物裂解后获得的三个单独片段（分子量范围为7000至23000）进行的抑制研究表明，肽F-CB3中至少存在三个不同的抗原决定簇。用胰蛋白酶消化肽F-CB3后，其仍保留了75%的最大抑制能力。肽F-CB3从纤维蛋白原分子中被溴化氰释放后以及进一步片段化后，其抗原活性没有变化，这大概是由于存在几个连续的抗原决定簇，但不能完全排除构象决定簇的存在。由于在牛和人肽F-B3之间未观察到交叉反应，因此可以预期它们的氨基酸序列存在相当大的差异。
