title: Purification and characterization of subcomponent Clq of the first component of bovine complement.
abstract: Bovine complement subcomponent C1q was purified, in a highly hemolytically active form, by a combination of precipitation with EGTA, ion-exchange chromatography, and gel filtration. Yield ranged from 22 to 28% as protein amounts, and the activity of final preparations was in the range of 2 X 10(13)-4 X 10(13) effective molecules/mg. The molecular weight of undissociated C1q was 407,000, as determined by polyacrylamide gel electrophoresis containing sodium dodecyl sulfate (SDS). C1q was shown to be composed of two non-covalently linked subunits of approximately 46,000 and 45,000 molecular weights in a molar ratio of 2 : 1. On reduction, the higher molecular weight subunit gave two chains having approximate molecular weights of 23,600 and 22,200 in equimolar ratio, and the lower molecular weight subunit gave one chain with a molecular weight of approximately 22,000. C1q contained hydroxyproline, hydroxylysine, a high percentage of glycine and approximately 9% carbohydrate and 14.8% nitrogen. The absorption coefficient (A 1% 1cm) in 300 mM NaCl was found to be 7.3 +/- 0.12 at 280 nm. From these results, overall molecular structure of bovine C1q looks similar to that of human complement subcomponent C1q.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003166:Complement Activating Enzymes / Q000302:isolation & purification; D015922:Complement C1q; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008970:Molecular Weight
chemical_list: D000596:Amino Acids; D002241:Carbohydrates; D015922:Complement C1q; D003166:Complement Activating Enzymes