Isolation and characterization of rabbit H of the alternative complement pathway.
Rabbit factor H, a control protein of the alternative complement pathway, was isolated from rabbit serum by polyethylene glycol precipitation, DEAE-Sephacel chromatography, and gel chromatography on Sephadex G200. The protein migrated as a single-chain polypeptide with a molecular weight of 160,000 on sodium dodecyl sulfate-gel electrophoresis with Laemmli's buffer system, but hardly migrated into the gel with Fairbanks' buffer system. Physical and chemical properties of rabbit H were similar to those of human H, except that fragments produced by limited tryptic digestion from rabbit H had different molecular sizes from those produced from human H. Significant species-specificity was observed in the functional activity of factor H; activation of the alternative complement pathway was inhibited more efficiently with homologous H than with heterologous H. In contrast, factor H inhibited the hemolysis of homologous erythrocytes less than that of heterologous erythrocytes.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003167:Complement Activation; D003180:Complement C3b Inactivator Proteins / Q000302:isolation & purification*; D003170:Complement Pathway, Alternative; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008970:Molecular Weight; D011817:Rabbits; D013045:Species Specificity
D000596:Amino Acids; D003180:Complement C3b Inactivator Proteins