Dissociation of C1 and concentration dependence of its activation kinetics.

Détails

ID Serval
serval:BIB_696731BCE6AC
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Dissociation of C1 and concentration dependence of its activation kinetics.
Périodique
Molecular Immunology
Auteur(s)
Kilchherr E., Fuchs H., Tschopp J., Engel J.
ISSN
0161-5890 (Print)
ISSN-L
0161-5890
Statut éditorial
Publié
Date de publication
1982
Volume
19
Numéro
5
Pages
683-691
Langue
anglais
Résumé
The activation of the zymogen C1s to the enzyme C1s in the human C1 complex [C1q(c1rC1s)2] was studied as a function of the concentrations of (C1rC1s)2 and C1q which were saturated with oligomers of rabbit IgG. A large concentration dependence of the sigmoidal kinetics was observed in the 2-180 nM concentration range. This was explained by association-dissociation equilibria between the antibody-saturated C1q and various forms of the (C1rC1s)2 complex (unactivated to activated). The establishment of these equilibria (binding constant 2 x 10(7) M-1) was assumed to be fast as compared to the rates of the activation steps (rate constants 10(-3) and 10(-2) sec-1 at 30 degrees C). The fast re-equilibration of the C1 complex explains the finding that small amounts of antibody-saturated C1q catalysed the activation of large amounts of C1s. The interpretation of the kinetic results was supported by a direct demonstration of the dissociation of C1 into C1q and (C1rC1s)2 by analytical and density gradient centrifugation. No difference was found between the rates of activation and the dissociation properties of reconstituted C1 and C1 isolated from serum.
Mots-clé
Centrifugation, Density Gradient, Complement Activating Enzymes/metabolism, Complement Activation, Complement C1/metabolism, Complement C1q, Complement C1r, Complement C1s, Humans, Kinetics, Macromolecular Substances, Models, Biological, Protein Binding, Time Factors, Ultracentrifugation
Pubmed
Web of science
Création de la notice
24/01/2008 16:19
Dernière modification de la notice
20/08/2019 15:24
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