Further Studies on the Identification of the Subcomponents of the First Component of Complement After Affinity Chromatography of Human Serum on IgG-Sepharose

• Published in: The Journal of immunology (1950) Vol. 118; no. 5; pp. 1722 - 1727
• Main Authors: Taylor, P. A, Fink, S, Bing, D. H, Painter, R. H
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 01.05.1977
• Subjects: Chromatography, Affinity; Chromatography, DEAE-Cellulose; Complement C1 - isolation & purification; Complement C1 - metabolism; Complement System Proteins - isolation & purification; Electrophoresis, Polyacrylamide Gel; Esterases - metabolism; Hemolysis; Humans; Immunoelectrophoresis; Immunoglobulin G; In Vitro Techniques; Molecular Weight; Trypsin Inhibitors
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.118.5.1722

Affinity chromatography of serum on IgG 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 has previously been shown to contain C1s and a novel protein believed to be part of the C1 complex and called C1t. C1r has now been located in pool II and these three proteins were purified by DEAE cellulose chromatography. C1r and C1s were recovered in the proenzyme form and their identity was established by SDS 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.