Tenner A J, Lesavre P H, Cooper N R
J Immunol. 1981 Aug;127(2):648-53.
A new procedure for isolating human C1q from serum or plasma is described. The method, that is highly selective, rapid and involves minimal handling, yields fully active, immunoglobulin-free unaggregated C1q. Several different methods of radiolabeling C1q are compared. These include two methods selective for tyrosine residues, two that label lysine residues, and a method that labels sialic acid residues. The effect of each of the labeling procedures on C1q hemolytic activity was assessed. Also appraised for each method was the ability of the labeled molecules to bind to antibody sensitized cells and to interact with C1r and C1s to form C1. The distribution of each of the radiolabels among the three polypeptide chains of C1q and between the collagenous and globular regions of C1q was determined. Methods were identified that selectively labeled the globular portion of either the A or C polypeptide chain of the C1q molecule without loss of functional activity. Another of the methods labeled all three polypeptide chains relatively uniformly without significant loss of activity.
本文描述了一种从血清或血浆中分离人C1q的新方法。该方法具有高度选择性、快速且操作简便，可产生完全活性、无免疫球蛋白且未聚集的C1q。比较了几种不同的C1q放射性标记方法。这些方法包括两种对酪氨酸残基有选择性的方法、两种标记赖氨酸残基的方法以及一种标记唾液酸残基的方法。评估了每种标记方法对C1q溶血活性的影响。还评估了每种方法中标记分子与抗体致敏细胞结合以及与C1r和C1s相互作用形成C1的能力。确定了每种放射性标记在C1q的三条多肽链之间以及C1q的胶原区和球状区之间的分布。已鉴定出一些方法，这些方法可选择性地标记C1q分子A或C多肽链的球状部分而不丧失功能活性。另一种方法相对均匀地标记所有三条多肽链且活性无明显损失。
