Effects of zinc on factor I cofactor activity of C4b-binding protein and factor H.
Article Details
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Blom AM, Kask L, Ramesh B, Hillarp A
Effects of zinc on factor I cofactor activity of C4b-binding protein and factor H.
Arch Biochem Biophys. 2003 Oct 15;418(2):108-18.
- PubMed ID
- 14522582 [ View in PubMed]
- Abstract
Complement inhibition is to a large extent achieved by proteolytic degradation of activated complement factors C3b and C4b by factor I (FI). This reaction requires a cofactor protein that binds C3b/C4b. We found that the cofactor activity of C4b-binding protein towards C4b/C3b and factor H towards C3b increase at micromolar concentrations of Zn(2+) and are abolished at 2 mM Zn(2+) and above. 65Zn(2+) bound to C3b and C4b molecules but not the cofactors or FI when they were immobilized in a native form on a nitrocellulose membrane. Zn(2+) binding constants for C3met (0.2 microM) and C4met (0.1 microM) were determined using fluorescent chelator. It appears that higher cofactor activity at low zinc concentrations is due to an increase of affinity between C4b/C3b and cofactor proteins as assessed by surface plasmon resonance. Inhibition of the reaction seen at higher concentrations is due to aggregation of C4b/C3b.
DrugBank Data that Cites this Article
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Zinc C4b-binding protein alpha chain Protein Humans UnknownNot Available Details Zinc C4b-binding protein beta chain Protein Humans UnknownNot Available Details Zinc Complement C4-B Protein Humans UnknownNot Available Details Zinc acetate C4b-binding protein alpha chain Protein Humans UnknownNot Available Details Zinc acetate C4b-binding protein beta chain Protein Humans UnknownNot Available Details Zinc acetate Complement C4-B Protein Humans UnknownNot Available Details Zinc chloride C4b-binding protein alpha chain Protein Humans UnknownModulatorDetails Zinc chloride C4b-binding protein beta chain Protein Humans UnknownModulatorDetails Zinc chloride Complement C4-B Protein Humans UnknownModulatorDetails Zinc sulfate, unspecified form C4b-binding protein alpha chain Protein Humans UnknownModulatorDetails Zinc sulfate, unspecified form C4b-binding protein beta chain Protein Humans UnknownModulatorDetails Zinc sulfate, unspecified form Complement C4-B Protein Humans UnknownModulatorDetails