Mechanism-based inhibition of monoamine oxidase by 3-aryl-Delta3-pyrrolines.

The compound 1-methyl-3-phenyl-Delta3-pyrroline and its 4-chlorophenyl analogue appear to act as irreversible inhibitors of monoamine oxidase B (MAO B) in mitochondria of rat liver. The compounds are metabolized by MAO B and concomitantly inhibit the enzyme in what seems to be a two-step process. The metabolic end product of this process is the corresponding pyrrole. This inhibition process is considered in the light of possible intermediates formed during the enzymic oxidation, and comparisons are made with the structurally analogous neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.