Knobel H R, Villiger W, Isliker H
Eur J Immunol. 1975 Jan;5(1):78-82. doi: 10.1002/eji.1830050119.
Five differently isolated and purified human C1q preparations were examined by electron microscopy and analyzed by polyacrylamide gel electrophoresis in 0.1% sodium dodecyl sulfate and 0.5 M urea. The amino acid and carbohydrate composition of C1q purified by the DNA method are reported and compared with results obtained on C1q isolated by other procedures. Electron microscopy showed that all C1q preparations had six peripheral subunits connected by fibrillar strands to a central subunit. The presence of small amounts of dimers was also observed. The physico-chemical properties of the molecule are independent of the purification method used. The five C1q preparations labeled with 125I in presence of lactoperoxidase formed two types of noncovalently linked subunits. In each case the smaller (central) subunit contained over thirty times as much radioactivity as the larger (peripheral) subunit supposed to interact with immune complexes. Reduction and alkylation confirmed for each preparation the presence of three polypeptide chains, the smaller of which contained essentially all radioactivity.
通过电子显微镜检查了五种不同分离和纯化的人C1q制剂，并在0.1%十二烷基硫酸钠和0.5M尿素中进行聚丙烯酰胺凝胶电泳分析。报道了通过DNA方法纯化的C1q的氨基酸和碳水化合物组成，并与通过其他程序分离的C1q的结果进行了比较。电子显微镜显示，所有C1q制剂都有六个外周亚基通过纤维状链连接到一个中央亚基。还观察到少量二聚体的存在。该分子的物理化学性质与所用的纯化方法无关。在乳过氧化物酶存在下用125I标记的五种C1q制剂形成了两种非共价连接的亚基。在每种情况下，较小的（中央）亚基所含放射性比较大的（外周）亚基多三十多倍，而较大的亚基应该与免疫复合物相互作用。还原和烷基化证实每种制剂都存在三条多肽链，其中较小的一条基本上含有所有放射性。
