Effect of neurotoxic metal ions on the proteolytic activities of the 20S proteasome from bovine brain
| Autor: | Nobili C, Mauro Angeletti, Evandro Fioretti, Manila Amici, Giulio Lupidi, Anna Maria Eleuteri, Forti K |
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| Jazyk: | angličtina |
| Rok vydání: | 2002 |
| Předmět: |
Proteasome Endopeptidase Complex
Metal ions in aqueous solution Blotting Western Oxidative phosphorylation medicine.disease_cause Biochemistry Catalysis Ferrous Inorganic Chemistry Hydrolysis Alzheimer Disease Multienzyme Complexes Casein Endopeptidases Hydrolase medicine Animals Brain Chemistry chemistry.chemical_classification Superoxide Dismutase Caseins Free Radical Scavengers Amino acid Cysteine Endopeptidases Oxidative Stress chemistry Metals Cattle Electrophoresis Polyacrylamide Gel Oxidation-Reduction Oxidative stress |
| Popis: | The effect of oxidative stress induced by neurotoxic metal ions on the properties of the brain 20S proteasome or multicatalytic proteinase complex (MPC) has been studied. Exposure of the 20S proteasome to increasing amounts of Fe(III), Fe(II), Cu(II) or Zn(II) affects its main hydrolytic activities: trypsin-like (T-L), chymotrypsin-like (ChT-L), peptidylglutamyl-peptide hydrolase (PGPH), branched-chain amino acid preferring (BrAAP) and caseinolytic activities, although in different ways. T-L activity showed gradual activation by both iron ions but inhibition by Cu(II) and Zn(II). ChT-L and PGPH activities were inhibited whereas BrAAP activity was widely activated by all the tested metal salts except for zinc ions. Moreover, the exposure to ferrous salt increased the degradation rate of casein. The functional effects appear to be linked to oxidation-induced modifications, as demonstrated by an increase of carbonyl groups following the exposure to metal ions. In addition, modifications induced by ferrous salt on the catalytic subunits were also supported by western blot analyses performed using anti-X, anti-Y and anti-Z antibodies. The results obtained clearly indicate that metal-catalyzed oxidation strongly affects the functions of the brain 20S proteasome, even though the catalytic subunits seem to be differently influenced by oxidative phenomena. |
| Databáze: | OpenAIRE |
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