FURTHER-STUDIES ON IDENTIFICATION OF SUBCOMPONENTS OF 1ST COMPONENT OF COMPLEMENT AFTER AFFINITY CHROMATOGRAPHY OF HUMAN-SERUM ON IGG-SEPHAROSE

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 118  (5) , 1722-1727
Abstract
Affinity chromatography of serum on Ig[immunoglobulin]G covalently linked to Sepharose results in the retention of the proteins of the first component of complement (C1). A fraction called pool II is eluted from this column with 0.025 M EDTA and was previously shown to contain C1s [s fragment of C1] and a novel protein believed to be part of the C1 complex and called C1t. C1r was located in these experiments in pool II, and these 3 proteins were purified by DEAE cellulose chromatography. C1r and C1s were recovered in the proenzyme form and their identity was established by SDS [sodium dodecyl sulfate] polyacrylamide gel electrophoresis before and after reduction and alkylation, and on the basis of their esterolytic activities toward different substrates. The properties of C1r from pool II are contrasted with those of the protein recovered from the pool III eluate of the affinity column and previously thought to be C1r.