[Molecular weight of mitochondrial type B MAO in various organs of guinea pig].
Molecular weights of mitochondrial type B monoamine oxidase (MAO) in guinea pig brain, liver and kidney were estimated, and their identities and multiplicity were studied. We ascertained what concentration of 3H-pargyline bound to type B MAO specifically from the inhibition curve toward serotonin (5-HT) and beta-phenylethylamine (beta-PEA) by pargyline. Pargyline irreversibly binds to FAD in MAO at a one to one molecular ratio. 3H-pargyline bound to type B MAO specifically and irreversibly by incubation for 5 hr at 37 degrees C, and SDS-disc electrophoresis was carried out using 3H-pargyline as a tracer. The molecular weight of MAO was estimated after specific binding of pargyline was corrected for non-specific binding. The molecular weight of type B MAO in every organ was found to be 60,000, giving a single peak after solubilization with 6% SDS, but several peaks at higher molecular weight were found in each organ after solubilization with 2% SDS. In the brain, there appeared to be a peak of 100,000, and it was suggested that the MAO existed as a dimer which was composed of a FAD containing subunit and a low molecular weight subunit containing no FAD. In the liver, there appeared to be peaks of 120,000 and 240,000, and it was suggested that the MAO existed as a dimer and tetramer. In the kidney, there appeared to be a peak of 180,000, and MAO was suggested to exist as a trimer.
D000818:Animals; D001921:Brain / Q000201:enzymology*; D055598:Chemical Phenomena; D002621:Chemistry; D004589:Electrophoresis, Disc; D006168:Guinea Pigs; D007527:Isoenzymes / Q000302:isolation & purification*; D007668:Kidney / Q000201:enzymology*; D008297:Male; D008928:Mitochondria / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology*; D008970:Molecular Weight; D008995:Monoamine Oxidase / Q000302:isolation & purification*; D009928:Organ Specificity
D007527:Isoenzymes; D008995:Monoamine Oxidase