Campbell R D, Booth N A, Fothergill J E
Biochem J. 1979 Dec 1;183(3):579-88. doi: 10.1042/bj1830579.
Bovine C1s, a subcomponent of the first component of complement, was purified in good yield by a combination of euglobulin precipitation and ion-exchange and molecular-sieve chromatography. Approx. 10 mg can be obtained from 3 litres of serum, representing a yield of 11%. The C1s is obtained in zymogen form, with a mol.wt. of 85000-88000, determined by gel filtration and SDS/polyacrylamide-gel electrophoresis. It is haemolytically active when tested with human C1q and C1r. Activation can be achieved by incubation with human C1r, resulting in cleavage of the C1s chain into two chains of 65000 and 27000 mol.wt. and the generation of an isoleucine N-terminal residue on the smaller chain. Active C1s binds an equimolar amount of di-isopropyl phosphorfluoridate to the smaller chain, which is the C-terminal part in the zymogen. The chains can be separated by ion-exchange in 8 M-urea. All of these characteristics show that bovine C1s is very similar to its human counterpart.
牛C1s是补体第一成分的一个亚组分，通过优球蛋白沉淀、离子交换和分子筛色谱相结合的方法得以高产率纯化。从3升血清中大约可获得10毫克，产率为11%。所获得的C1s为酶原形式，通过凝胶过滤和SDS/聚丙烯酰胺凝胶电泳测定，其分子量为85000 - 88000。用人类C1q和C1r检测时具有溶血活性。与人类C1r一起温育可实现激活，导致C1s链裂解为分子量为65000和27000的两条链，并在较小的链上产生异亮氨酸N端残基。活性C1s与等摩尔量的二异丙基氟磷酸酯结合到较小的链上，该链在酶原中是C端部分。这些链可在8M尿素中通过离子交换分离。所有这些特性表明牛C1s与其人类对应物非常相似。
