Schreiber R D, Müller-Eberhard H J
J Exp Med. 1974 Nov 1;140(5):1324-35. doi: 10.1084/jem.140.5.1324.
The fourth component of human complement (C4) was shown to be composed of three distinct polypeptide chains linked by disulfide bonds and noncovalent forces. The sum of the molecular weights of the chains equalled that of the intact molecule. The mol wt of the alpha-, beta-, and gamma-chains were respectively, 93,000, 78,000, and 33,000 daltons. Action of C1s on C4 affected only the alpha-chain, reducing its mol wt to 87,000 daltons. The size of the activation peptide. C4a, is therefore estimated to be 6,000 and that of the major fragment C4b, 198,000 daltons. Periodic acid-Schiff-stained SDS polyacrylamide gels of reduced C4 revealed carbohydrate to be associated with all three chains. A modification of the original method of isolation of C4 is presented.
人补体的第四成分（C4）由通过二硫键和非共价力相连的三条不同多肽链组成。这些链的分子量总和等于完整分子的分子量。α、β和γ链的分子量分别为93,000、78,000和33,000道尔顿。C1s对C4的作用仅影响α链，使其分子量降至87,000道尔顿。因此，活化肽C4a的大小估计为6,000，主要片段C4b的大小为198,000道尔顿。经高碘酸-希夫染色的还原C4的十二烷基硫酸钠-聚丙烯酰胺凝胶显示，碳水化合物与所有三条链相关。本文介绍了一种对原始C4分离方法的改进。
