title: Isolation and characterization of highly stable rabbit C1q.
abstract: Rabbit C1q has been isolated by techniques which retain elements of previous isolation methods along with novel procedures incorporated to yield stable, non-aggregating, highly purified and biologically active C1q. The procedure involves euglobulin preparation by dialysis of serum and two column chromatographies, DEAE-Sephadex and Ultragel ACA 34. The method results in yields of C1q from rabbit sera of 20-30%. Ouchterlony analysis, sedimentation velocity experiments, equilibrium ultracentrifuge molecular weight analysis, SDS, polyacrylamide gel electrophoresis and isoelectric focusing experiments indicate the presence of only a single component, which has all the physical characteristics previously reported for C1q. The preparation has all the biological characteristics of C1q such as the ability to agglutinate IgG-coated latex particles and to restore hemolytic activity to RC1q serum. Preparations obtained by this procedure are stable to freezing (-70 degrees C) for extended periods of time and show no evidence of aggregation upon thawing following periods of storage of up to 6 months. Mild acetylation and handling of preparations for extended periods at 37 degrees C and 45 degrees C indicate no evidence of aggregation or loss of agglutinating and hemolytic activities. Preparations so isolated meet all the criteria required for critical physical-chemical studies of this protein.
mesh_terms: D000818:Animals; D002852:Chromatography, Ion Exchange; D003172:Complement C1 / Q000302:isolation & purification* / Q000378:metabolism; D005782:Gels; D007525:Isoelectric Focusing; D008722:Methods; D011817:Rabbits; D013997:Time Factors
chemical_list: D003172:Complement C1; D005782:Gels