Purification, identification and characterization of chicken C1q, a subcomponent of the first component of complement.
A component, having the equivalent haemolytic activity to that of human complement subcomponent C1q, was purified by a combination of precipitation with EGTA, gel filtration, ion exchange and adsorption chromatography from chicken serum. Yields ranged from 8 to 15 mg/litre of serum. The finally purified preparation generates full Cl haemolytic activity when assayed with human complement subcomponents C1r and C1s, and have been identified as chicken C1q. The molecular weight of undissociated C1q, as estimated on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDS), is 504,000. Under dissociating but non-reducing conditions, the C1q was shown to consist of 2 subunits having molecular weights of 52,700 and 51,200 in a molar ratio of 2:1. On reduction, the 52,700 molecular weight subunit gave chains with molecular weights of 25,900 and 24,800 in equimolar ratio, and the 51,200 molecular weight subunit decreased to 24,800. The C1q contains hydroxyproline, hydroxylysine, a high percentage of glycine and approximately 7% carbohydrate. Collagenase digestion of C1q caused a rapid loss of haemolytic activity and produced much smaller peptide fragments.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001681:Biological Assay; D002241:Carbohydrates / Q000032:analysis; D002645:Chickens / Q000502:physiology*; D003166:Complement Activating Enzymes / Q000302:isolation & purification* / Q000502:physiology; D015922:Complement C1q; D005998:Glycine / Q000032:analysis; D006461:Hemolysis; D006801:Humans; D006909:Hydroxyproline / Q000032:analysis; D003012:Microbial Collagenase / Q000378:metabolism
D000596:Amino Acids; D002241:Carbohydrates; D015922:Complement C1q; D003166:Complement Activating Enzymes; D003012:Microbial Collagenase; D006909:Hydroxyproline; D005998:Glycine