Isolation of decay-accelerating factor (DAF) from rabbit erythrocyte membranes.
A regulatory protein purified from rabbit erythrocyte stroma had decay-accelerating activity to C5 convertases on hemolytic intermediate cells (EAC1-3b, P). Its molecular weight was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under non-reducing conditions to be 66,000, slightly smaller than that of human decay-accelerating factor (DAF). The amino acid composition of the protein resembled that of human DAF. The protein was incorporated into sheep erythrocytes. The incorporation and the decay-accelerating activity were inhibited by low density lipoprotein. It did not bind to rabbit C3-Sepharose in a column under conditions in which human CR1 bound, but its interaction with rabbit C3 was evident from the retardation of its elution from the column. These results indicate that the protein purified from rabbit erythrocyte stroma was DAF.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D018958:CD55 Antigens; D003167:Complement Activation; D003176:Complement C3 / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000032:analysis*; D008077:Lipoproteins, LDL / Q000494:pharmacology; D008565:Membrane Proteins / Q000302:isolation & purification*; D008970:Molecular Weight; D011817:Rabbits; D014357:Trypsin
D000596:Amino Acids; D018958:CD55 Antigens; D003176:Complement C3; D008077:Lipoproteins, LDL; D008565:Membrane Proteins; D014357:Trypsin