Inhibition and inactivation of monoamine oxidase by 3-amino-1-phenyl-prop-1-enes
| Autor: | Carvell H. Williams, F. R. Colette Backwell, Jill Lawson |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Benzylamines
Monoamine Oxidase Inhibitors Monoamine oxidase Stereochemistry Kinetics Biophysics Mitochondria Liver Biochemistry Aldehyde Methylamines Structural Biology Animals Acrolein Monoamine Oxidase Molecular Biology chemistry.chemical_classification Binding Sites Propylamines biology Chemistry Substrate (chemistry) Stereoisomerism Rats Enzyme Liver Benzaldehydes biology.protein Cattle Amine gas treating Monoamine oxidase B Monoamine oxidase A |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology. 1119:111-117 |
| ISSN: | 0167-4838 |
| DOI: | 10.1016/0167-4838(92)90379-r |
| Popis: | We have previously shown that E -3-amino-1-phenyl-prop-1-ene(E-cinnamylamine) is readily oxidised by monoamine oxidase (MAO) type B from either rat or bovine liver (Williams et al. (1988), Biochem. J. 256, 411–415) in each case producing a non-linear progress curve which was attributed to inhibition by the reaction product E -cinnamaldehyde. We have now found that the although this aldehyde inhibits MAO B competitively ( K i 0.017mM) this cannot account for the inhibitory process, since during a 60 min incubation with the substrate (0.5 mM; K m , 0.074 mM) more than 95% inhibition of MAO B was observed and the concentration of aldehyde had reached approx. 0.025 mM. Inhibition was relieved either by dialysis or dilution of inhibited samples. The activity of MAO A from rat liver was largely unaffected by E -cinnamylamine. Oxidation of N -methyl- E -cinnamylamine and its Z-isomer by MAO B produced progress curves similar to that obtained with the primary amine, but in these cases inhibition was not reversed either by dilution or dialysis. Partition ratios for the pair of N -methyl isomers with bovine MAO B were calculated to be 1640 ( E -isomer) and 1430 (Z-isomer). The time-dependent inhibition process for all three amines obeyed pseudo-first-order kinetics. A tritiated form of N -methyl- E -cinnamylamine, incubated with MAO B from bovine liver, resulted in incorporation of radioactivity into the enzyme. This labelling was stable to dialysis and to SDS-PAGE. |
| Databáze: | OpenAIRE |
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