title: Isolation and characterization of the third component of bovine complement.
abstract: C3 was obtained from bovine serum by polyethylene glycol precipitation and chromatography on DEAE-Sephadex A-50, CM-Sephadex A-50 and Sephacryl S-200. The protein has a molecular weight of 183,000 (alpha-chain 114,000 and beta-chain 69,000). A CVF-induced bovine C3 convertase (Sepharose-CVF.Bb) cleaved C3 into C3a (11,000) and C3b (172,000) as shown by SDS-polyacrylamide gel electrophoresis. Isoelectricfocusing of C3 demonstrated at least three electrophoretic variants with pI 6.55-6.85. The isolated protein promoted the formation and action of a C3 convertase in the presence of purified bovine factors B and D. A monospecific antiserum prepared in rabbits failed to cross react with human C3 or CVF. C3c was identified as a contaminant during the isolation of C3.
mesh_terms: D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D003176:Complement C3 / Q000302:isolation & purification* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D007525:Isoelectric Focusing; D046911:Macromolecular Substances; D008970:Molecular Weight
chemical_list: D003176:Complement C3; D046911:Macromolecular Substances