title: Mechanism-based inactivation of porcine kidney diamine oxidase by 1,4-diamino-2-butene.
abstract: Cis- and trans-1,4-diamino-2-butene are substrates and potent inactivators of porcine kidney diamine oxidase. Evidence from absorption and NMR spectra indicates that both are oxidized to pyrrole. Both substrates are irreversible mechanism-based inactivators of the enzyme, although the trans isomer is more potent and results in complete inactivation in a reaction which follows pseudo-first-order kinetics with an apparent Ki of 0.34 mM and a second-order inactivation constant of 500 M-1 s-1. Under the same conditions, 46% of the activity remains when the enzyme is reacted with cis-1,4-diamino-2-butene. Trans-4-amino-2-butenal, the product of oxidation of the trans diamine, has been synthesized and shown to undergo cyclization to pyrrole in a concentration-dependent manner, approaching second-order at low concentrations. Trans-4-amino-2-butenal is itself a potent irreversible inhibitor with IC50 of 2.5 microM. We propose that the irreversible inactivation by both cis- and trans-1,4-diamino-2-butene involves attack by a protein-based nucleophilic residue on the unsaturated aminoenal products of the enzymatic reactions, resulting in a covalent adduct. Cyclization of the cis-aminoenal to pyrrole is much more rapid than in the trans case, thus it is less available for inhibitory reaction with the protein.
mesh_terms: D000447:Aldehydes / Q000378:metabolism / Q000494:pharmacology; D000499:Allylamine / Q000494:pharmacology; D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D000693:Anaerobiosis; D000818:Animals; D002103:Cadaverine / Q000378:metabolism / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010293:Pargyline / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D011437:Propylamines / Q000378:metabolism / Q000494:pharmacology; D011700:Putrescine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D011758:Pyrroles / Q000032:analysis; D013053:Spectrophotometry; D013552:Swine
chemical_list: C097000:4-amino-2-butenal; D000447:Aldehydes; D004791:Enzyme Inhibitors; C097001:N,N-dimethyl-1,4-diamino-2-butene; D011437:Propylamines; D011758:Pyrroles; C021006:diaminobutene; C009054:propargylamine; D000499:Allylamine; D010293:Pargyline; D006861:Hydrogen Peroxide; D006631:Amine Oxidase (Copper-Containing); D002103:Cadaverine; D011700:Putrescine