Purification and characterization of subcomponent C1q of the first component of mouse complement

Abstract

1. Mouse C1q, a subcomponent of the first component of complement, has been purified in a highly haemolytically active form by a combination of precipitation with EGTA, ion-exchange chromatography and gel filtration. Yields ranged from 3 to 5 mg/200 ml of serum, and the activity of final preparations was in the range of 2 X 10(13)-4 X 10(13) C1q effective molecules/mg. 2. The molecular weight of mouse C1q was 439 500 +/- 1586, as determined by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. 3. Mouse C1q was shown to be composed of non-covalently linked subunits, all being in the molecular-weight range 45 000-46 000, and three covalently linked chains each having a molecular weight of approx. 23 000 as determined on polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate by using non-covalently and covalently linked subunits of human C1q as markers with known molecular weights calculated theoretically previously [Porter & Reid (1978) Nature (London) 275, 699-704]. 4. Mouse C1q contained hydroxyproline, hydroxylysine, a high percentage of glycine and approx. 9% carbohydrate. The absorption coefficient and nitrogen content of C1q were also determined.

C1q, the recognition subcomponent of the classical pathway of complement, drives microglial activation

“…Rat C1q was purified from whole rat serum using a protocol adapted from that described by Yonemasu and Sasaki (1981). Briefly, 100 ml serum was dialyzed against 3 × 2 liters of 10 mM EGTA over 48 hr.…”

Isolation, molecular properties and allotype of mouse C1q.

“…We noticed, however, firstly that mouse Clq showed three distinctive bands on SDS-PAGE (Seino et al 1980). Yonemasu and Sasaki (1981) reported that non-reduced mouse Clq gave two intensely stained bands with two faintly stained bands between them on SDS-PAGE. At first, we could not recognize whether it gave two or three bands in standard short gels (0.5 X 6.0 cm), but we found three distinctive bands by extending the distances between the bands in longer gels (0.…”

“…McManus and Nakane (1980) isolated mouse Clq and demonstrated negatively stained ultrastructural appearance of the mouse Clq consisting of six globular units connected by strands similar to human Clq. Yonemasu and Sasaki (1981) also purified mouse Clq and described its biochemical properties and a structural finding that it gave two intensely stained bands with two faintly stained bands between them on SDS-PAGE in non-reducing condition. In this study, we isolated Clq from mouse EDTA plasma by a precipitation with polyethyleneglycol and column chromatography, and demonstrated that the purified mouse Clq shows three bands different from human Clq on SDS-PAGE in the non-reducing condition.…”

Immunochemical Analyses of Prolidase Deficiency Sera

“…Antisera against human whole serum, albumin, Clq and C3 were produced in rabbits according to a reported immunization schedule (10,11). Antisera against human o l-acid glycoprotein, aI-antitrypsin, Go-globulin, a l-antichymotrypsin, ceruloplasmin, haptoglobin, a2-macroglobulin, hemopexin, transferrin and IgA were purchased from HoechstJapan (Tokyo, Japan).…”