Timpl R, Hahn E, Gollwitzer R
Eur J Biochem. 1975 Feb 21;51(2):617-23. doi: 10.1111/j.1432-1033.1975.tb03964.x.
Rabbit antibodies to bovine fibrinogen were used to study the antigenic activity of four cyanogen bromide peptides containing the disulfide regions of this molecule. In precipitation tests the highest activity was associated with the peptide F-CB3 which is exclusively derived from the alpha-chain. Reduction of the single disulfide bridge in peptide F-CB3 did not influence its serologic activity. Weaker reactions were observed with the N-terminal multichain peptide F-CB1. The antigenicity of peptide F-CB1 was not affected by removal of fibrinopeptides A and B but it was lost after reduction. The immunological activity of the multichain peptide F-CB2 was even less than that of peptide F-CB1 and the antigenic determinants were destroyed by reduction. A large fragment essentially composed of peptides F-CB1 and F-CB2 could be obtained by limited cyanogen bromide cleavage and showed considerably better immunological activity than peptides F-CB1 and F-CB2 together. Apparently no activity was associated with a mixture of small hydrophobic, disulfide-loop peptides tentatively called peptide F-CB4. The large loss of antigenic activity in cyanogen bromide digests of fibrinogen suggests that the disulfide-stabilized regions do not have an important role in maintaining conformational antigenic determinants of fibroinogen. Changes in noncovalently stabilized conformation requiring uncleaved chains is considered as a possible reason for the findings observed.
用抗牛纤维蛋白原的兔抗体研究了含有该分子二硫键区域的四种溴化氰肽的抗原活性。在沉淀试验中，最高活性与仅来源于α链的肽F-CB3相关。肽F-CB3中单个二硫键的还原不影响其血清学活性。观察到与N端多链肽F-CB1的反应较弱。肽F-CB1的抗原性不受纤维蛋白肽A和B去除的影响，但还原后丧失。多链肽F-CB2的免疫活性甚至低于肽F-CB1，其抗原决定簇在还原后被破坏。通过有限的溴化氰裂解可获得基本上由肽F-CB1和F-CB2组成的大片段，其免疫活性明显优于肽F-CB1和F-CB2两者之和。显然，一种暂称为肽F-CB4的小疏水二硫键环肽混合物没有活性。纤维蛋白原溴化氰消化物中抗原活性的大量丧失表明，二硫键稳定区域在维持纤维蛋白原构象抗原决定簇方面没有重要作用。需要未切割链的非共价稳定构象的变化被认为是观察到这些发现的一个可能原因。
