Mitochondrial Monoamine Oxidase INACTIVATION BY PARGYLINE. ADDUCT FORMATION

摘要: Abstract Pargyline (N-benzyl-N-methyl-2-propynylamine), known to react stoichiometrically and irreversibly with the mitochondrial monoamine oxidase of bovine kidney, involving simultaneously enzyme's flavin component, (Hellerman, L., Erwin, V. G. (1968) J. Biol. Chem. 243, 5234–5243), has been shown inactivate by forming a stable adduct residue. Thus, reaction pargyline an equivalent quantity produced "bleaching" at 455 nm appearance strongly absorbing species 410 nm. Use excess [7-14C]pargyline gave 14C-protein product (1.1 residues inhibitor bound per enzyme equivalent.) Proteolysis 14C-labeled protein chromatographic fractionation peptides resulting revealed that most 14C label was associated fraction containing altered coenzyme now maximally 398 molar absorptivity approximately 29,000 cm-1 m-1. Given here also is procedure for preparation twice activity obtained previously (Erwin, G., Hellerman, L. (1967) 242, 4230–4238). Based on estimates concentration discontinuous titrations pargyline, respective values weight catalytic center (turnover) were calculated be 109,000 525 oxidation benzylamine in air pH 7.6 37°.