title: Spontaneous activation of reconstituted and serum C1 and the role of C1-inhibitor.
abstract: Evidence will be presented that first order, spontaneous activation of solution C1 at 37 degrees C under physiological conditions is a very slow process with a half-life of the order of one day and perhaps considerably longer. In addition, negative evidence will be presented showing that the formation of functionally significant levels of a complex between C1-Inhibitor and unactivated C1 does not occur. Such a complex had been previously postulated to explain the strong inhibition of the spontaneous activation of C1 which was observed upon the addition of C1-Inhibitor. Rather, we shall demonstrate that C1 catalytically activates C1, and that a critical role for C1-inhibitor is to complex with C1 to eliminate this autocatalytic reaction.
authors: Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.
authors: V N
authors: VN
authors: Schumaker
authors: Y
authors: Y
authors: Tseng
authors: P H
authors: PH
authors: Poon
authors: A C
authors: AC
authors: Bianchino
authors: P
authors: P
authors: Zavodszky
mesh_terms: D002384:Catalysis; D003167:Complement Activation; D003172:Complement C1 / Q000378:metabolism*; D003174:Complement C1 Inactivator Proteins / Q000502:physiology*; D003171:Complement Pathway, Classical; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D011485:Protein Binding
chemical_list: D003172:Complement C1; D003174:Complement C1 Inactivator Proteins