The in vitro inhibition of hepatic ferrochelatase by divalent lead and other soft metal ions
| Autor: | Reimer R. W. Gaertner, Bryan R. Hollebone |
|---|---|
| Rok vydání: | 1983 |
| Předmět: |
Sodium ascorbate
Iron Inorganic chemistry Lyases chemistry.chemical_element Zinc Divalent Metal chemistry.chemical_compound Animals Chelation Ferrous Compounds Binding site chemistry.chemical_classification Ionic radius biology Rats Inbred Strains General Medicine Ferrochelatase Rats Kinetics Lead Liver chemistry visual_art visual_art.visual_art_medium Biophysics biology.protein Mathematics |
| Zdroj: | Canadian Journal of Biochemistry and Cell Biology. 61:214-222 |
| ISSN: | 0714-7511 |
| DOI: | 10.1139/o83-030 |
| Popis: | A solubilized protein with ferrochelatase activity has been extracted from hepatic mitochondria of Sprague–Dawley rats. Under anerobic conditions in the presence of sodium ascorbate the ferrochelatase velocity was typically 1.8 nM∙min−1∙mg−1. The extract also displayed zinc chelatase activity of 1.2 nM∙min−1∙mg−1 without either anerobic conditions or ascorbate. In both cases substrate inhibition occurred for metal ion and deuteroporphyrin, but in the linear range a noncompetitive two-site mechanism was observed. The ferrochelatase activity is inhibited by divalent copper, mercury, and lead ions and the sodium salt of p-chloromercuribenzoate and is replaced by zinc chelation activity. This evidence suggests that the metal-binding site includes a thiol group. The inhibition of the site is greatest with Cu2+ and decreases with increasing ionic radius to Pb2+. This observation implies that the binding site is stereochemically adapted to the small Fe2+ ion and to some extent protected from larger, sulfur-binding ions which can inhibit ferrochelatase activity. |
| Databáze: | OpenAIRE |
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