Purification of human complement subcomponent C4

The purification and characterization of subcomponent C1s of the first component of bovine complement.

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 ...

Complement C 1 q subcomponent subunit A

Effect of thiol compounds on human complement component C4.

Thiol compounds have been investigated as inhibitors of the covalent binding reaction of human complement protein C4 using Sepharose-C1s as a combined activating and binding surface. o- and p-substituted aminothiophenols are equally effective inhibitors, whereas the m-substituted compound is a less potent inhibitor. The anti-hypertensive drug captopril is also shown to inhibit the covalent bind...

IgG and rabbit IgG in binding of complement subcomponent Clq

Treatment of covalently cross-linked or heat-aggregated oligomers of human IgG with 4 mMtetranitromethane abrogated their Clq-binding activity. In contrast, tetranitromethane modification of rabbit IgG oligomers, under identical conditions, had no effect upon their Clq-binding activity. The tetranitromethane treatment led to nitration of about ten tyrosine residues per IgG molecule in both spec...

Interaction between complement subcomponent C1q and bacterial lipopolysaccharides.

The heptose-less mutant of Escherichia coli, D31m4, bound complement subcomponent C1q and its collagen-like fragments (C1qCLF) with Ka values of 1.4 x 10(8) and 2.0 x 10(8) M-1 respectively. This binding was suppressed by chemical modification of C1q and C1qCLF using diethyl pyrocarbonate (DEPC). To investigate the role of lipopolysaccharides (LPS) in this binding, biosynthetically labelled [14...