Inhibition of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine metabolic activity of porcine FAD-containing monooxygenase by selective monoamine oxidase-B inhibitors.

The MPTP metabolic activity of porcine FAD-containing monooxygenase (FMO) (EC 1.14.13.8) was inhibited considerably by deprenyl and pargyline, selective MAO-B inhibitors, and they showed typical competitive inhibition. Deprenyl and pargyline, amine derivatives were also examined as to whether they are substrates for the FMO. It was found that deprenyl and pargyline are excellent substrates for the FMO. The Ki and Km values of deprenyl and pargyline for the FMO are 14 microM and 9 microM, and 14.3 microM and 11.6 microM, at pH 8.0 and 25 degrees C, respectively.