Mechanism-based inactivation of porcine kidney diamine oxidase by 1,4-diamino-2-butene
| Autor: | Lawrence M. Sayre, Durgesh V. Nadkarni, Frederick T. Greenaway, Zuwen He |
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| Rok vydání: | 1995 |
| Předmět: |
Stereochemistry
Swine Biophysics Kidney Biochemistry Enzyme catalysis Adduct Allylamine chemistry.chemical_compound Nucleophile Structural Biology Diamine Cadaverine Putrescine Animals Pyrroles Anaerobiosis Enzyme Inhibitors Molecular Biology Pyrrole Aldehydes Propylamines Chemistry Hydrogen Peroxide Kinetics Models Chemical Pargyline Covalent bond Spectrophotometry Amine Oxidase (Copper-Containing) Diamine oxidase Oxidation-Reduction Cis–trans isomerism |
| Zdroj: | Biochimica et biophysica acta. 1253(1) |
| ISSN: | 0006-3002 |
| Popis: | 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 K i 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-butena is itself a potent irreversible inhibitor with IC 50 of 2.5 μM. 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. |
| Databáze: | OpenAIRE |
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