The effect of lipid-depletion on the kinetic properties of rat liver monoamine oxidase-B.
The extraction of lipids from rat liver mitochondrial membranes by 2-butanone treatment inhibited the activity of membrane-bound monoamine oxidase -A but not -B. For the -B form, the apparent Michaelis constants of the enzyme towards oxygen and the maximum molecular turnover numbers obtained when beta-phenethylamine and benzylamine were used as substrates were not significantly changed by the lipid-depletion procedure, but the values of the Michaelis constant towards benzylamine was significantly increased after lipid-depletion. The differential sensitivity of beta-phenethylamine and benzylamine oxidation to inhibition by Tris-HCl was not changed after lipid-depletion. The results are consistent with the hypothesis that the mitochondrial membrane lipids, while essential for the activity of the -A form of the enzyme in rat liver, play a more subtle modulatory role in the activity of the -B form.
D000818:Animals; D002074:Butanones; D003010:Clorgyline / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008055:Lipids / Q000172:deficiency*; D008930:Mitochondria, Liver / Q000201:enzymology*; D008995:Monoamine Oxidase / Q000378:metabolism*; D051381:Rats; D012642:Selegiline / Q000494:pharmacology
D002074:Butanones; D008055:Lipids; D012642:Selegiline; D008995:Monoamine Oxidase; D003010:Clorgyline