Inhibition of copper/quinoprotein amine oxidases from Aspergillus niger by benzophenanthridine alkaloids
Language English Country Switzerland Media print
Document type Journal Article
- MeSH
- Alkaloids pharmacology MeSH
- Aspergillus niger enzymology MeSH
- Benzophenanthridines MeSH
- Phenanthridines pharmacology MeSH
- Amine Oxidase (Copper-Containing) antagonists & inhibitors MeSH
- Enzyme Inhibitors pharmacology MeSH
- Isoquinolines MeSH
- Dose-Response Relationship, Drug MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Alkaloids MeSH
- Benzophenanthridines MeSH
- chelerythrine MeSH Browser
- fagaronine MeSH Browser
- Phenanthridines MeSH
- Amine Oxidase (Copper-Containing) MeSH
- Enzyme Inhibitors MeSH
- Isoquinolines MeSH
- sanguinarine MeSH Browser
Inhibition of copper/quinoprotein amine oxidases (EC 1.4.3.6), AO-I (dimer 2 x 75 kDa) and AO-II (monomer 80 kDa), from the fungus Aspergillus niger by benzophenanthridine alkaloids sanguinarine, chelerythrine, and fagaronine were studied. For both amine oxidases the alkaloids showed reversible noncompetitive inhibition of n-hexylamine oxidation with Ki 0.6, 0.9 and 2.8 mM for sanguinarine, chelerythrine, and fagaronine, respectively. The values of the inhibition constants corresponded to pKR+ values for the iminium ion/pseudobase equilibrium of the alkaloids. Since thio-compounds protected the enzymes against this inhibition, the inhibition effect was ascribed to the interaction with a sulfhydryl group essential for the enzymatic activity.
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