Kerbiriou D M, Bouma B N, Griffin J H
J Biol Chem. 1980 May 10;255(9):3952-8.
Human plasm contains at least two distinct kininogens, designated high Mr and low Mr kininogens, that differ in their Mr and susceptibility to different kallikreins. By limited proteolysis, plasma kallikrein cleaves high Mr kininogen to liberate kinin and gives a molecule containing two disulfide-linked polypeptide chains. Following reduction and alkylation of the two-chain molecule, the heavy chain and the light chain were isolated, and antisera were raised in goats against the alkylated heavy and light chains. The anti-heavy chain antiserum immunoprecipitated both high Mr and low Mr kininogen, whereas the anti-light chain antiserum was specific for high Mr kininogen. Thus, the heavy chain of kinin-free high Mr kininogen and low Mr kininogen extensively share identical immunologic determinants. In contrast, the immunologic determinants of the isolated light chain are unique to high Mr kininogen. Using immunochemical techniques, it was shown that high Mr kininogen or the light chain derived from it forms a complex either with prekallikrein or with kallikrein. Titrations of prekallikrein or kallikrein with increasing amounts of either high Mr kininogen or its alkylated light chain indicated that the complexes contain equimolar amounts of each molecule. These results show that a single site for prekallikrein or kallikrein binding to high Mr kininogen resides in the light chain region of the molecule.
人血浆含有至少两种不同的激肽原，分别称为高分子量激肽原和低分子量激肽原，它们在分子量以及对不同激肽释放酶的敏感性方面存在差异。通过有限的蛋白水解作用，血浆激肽释放酶切割高分子量激肽原以释放激肽，并产生一个包含两条二硫键连接的多肽链的分子。在对该双链分子进行还原和烷基化处理后，分离出重链和轻链，并在山羊体内制备了针对烷基化重链和轻链的抗血清。抗重链抗血清能免疫沉淀高分子量激肽原和低分子量激肽原，而抗轻链抗血清则对高分子量激肽原具有特异性。因此，无激肽的高分子量激肽原和低分子量激肽原的重链广泛共享相同的免疫决定簇。相比之下，分离出的轻链的免疫决定簇是高分子量激肽原所特有的。使用免疫化学技术表明，高分子量激肽原或其衍生的轻链与前激肽释放酶或激肽释放酶形成复合物。用越来越多的高分子量激肽原或其烷基化轻链对前激肽释放酶或激肽释放酶进行滴定表明，这些复合物中每个分子的含量是等摩尔的。这些结果表明，前激肽释放酶或激肽释放酶与高分子量激肽原结合的单个位点位于该分子的轻链区域。
