Inhibitor Of Copper-containing Amine Oxidases Research Articles

Mutation of Arabidopsis Copper-Containing Amine Oxidase Gene AtCuAOδ Alters Polyamines, Reduces Gibberellin Content and Affects Development.

Polyamines (PAs) are essential metabolites in plants performing multiple functions during growth and development. Copper-containing amine oxidases (CuAOs) catalyse the catabolism of PAs and in Arabidopsis thaliana are encoded by a gene family. Two mutants of one gene family member, AtCuAOδ, showed delayed seed germination, leaf emergence, and flowering time. The height of the primary inflorescence shoot was reduced, and developmental leaf senescence was delayed. Siliques were significantly longer in mutant lines and contained more seeds. The phenotype of AtCuAOδ over-expressors was less affected. Before flowering, there was a significant increase in putrescine in AtCuAOδ mutant leaves compared to wild type (WT), while after flowering both spermidine and spermine concentrations were significantly higher than in WT leaves. The expression of GA (gibberellic acid) biosynthetic genes was repressed and the content of GA1, GA7, GA8, GA9, and GA20 was reduced in the mutants. The inhibitor of copper-containing amine oxidases, aminoguanidine hydrochloride, mimicked the effect of AtCuAOδ mutation on WT seed germination. Delayed germination, reduced shoot height, and delayed flowering in the mutants were rescued by GA3 treatment. These data strongly suggest AtCuAOδ is an important gene regulating PA homeostasis, and that a perturbation of PAs affects plant development through a reduction in GA biosynthesis.

Characterization and application of aminoamide-oxidizing enzyme from Aspergillus carbonarius AIU 205

We isolated Aspergillus carbonarius AIU 205 as a new producer of an enzyme catalyzing oxidative deamination of 4-aminobutanamide (4-ABAD) to 4-oxobutanamide with the subsequent release of ammonia and hydrogen peroxide. Since the strain produced three enzymes with different Km values for 4-ABAD, the enzyme with lowest Km value (0.31 mM) was purified and revealed certain remarkable properties. The enzyme also oxidized aliphatic monoamines, aromatic amines and aliphatic aminoalcohols, but did not oxidize l-amino acids and aliphatic diamines. The Vmax/Km values for aliphatic monoamines were higher than that for 4-ABAD, and the enzyme activity was strongly inhibited by inhibitors of copper-containing amine oxidases. Thus, it was concluded that the enzyme might belong to a group of copper-containing amine oxidase. The 4-ABAD oxidase activity of this enzyme was optimum at pH 7.0, and the enzyme activity at pH 6.0 was 65% of that at pH 7.0. The enzyme was useful for increasing the sensitivity of l-lysine assay using l-amino acid oxidase/monooxygenase from Pseudomonas sp. AIU 813.

Hydrazine and amphetamine binding to amine oxidases: old drugs with new prospects

Tranylcypromine (TCP), an amphetamine, is a reversible inhibitor of copper-containing amine oxidases. We have solved the structure of the complex of TCP with the amine oxidase from E. coli (ECAO) and shown that only the (+)-enantiomer of TCP binds. Kinetic studies on 2-phenylethylamine and TCP binding to wild-type ECAO and mutational variants fully support the model in which binding of the protonated amine is the first step in the catalytic cycle. Hydrazines are irreversible inhibitors of copper-containing amine oxidases. Binding of hydrazines leads to an adduct ("Adduct 1") with a chromophore at 430 nm which converts at higher pH to another adduct ("Adduct 2") with a chromophore at 520 nm. We have determined the structures of Adduct 1 and 2 for 2-hydrazinopyridine reacted with ECAO. It has been found that Adduct 1 corresponds to the hydrazone and azo tautomers whilst Adduct 2 corresponds to the azo tautomer coordinated to the active site copper. The implications of these results in developing more specific drugs are discussed.

Inhibition of diamine oxidases and polyamine oxidases by diamine-based compounds

This review reports on inhibitors of copper-containing amine oxidases and flavoprotein polyamine oxidases, which are structurally based on diamines. In the introduction, basic characteristics and classification of amine oxidases are described together with the significance of their synthetic inhibitors. The following text is divided into several chapters, which deal with diaminoketones, aza-diamines, unsaturated diamine analogs and diamines with heterocyclic substituents. Then it continues with diamine- and agmatine-based inhibitors of polyamine oxidases. Each chapter gives detailed information on the inhibition mode, potency and structural relationships. The conclusion points out possible roles of mechanism-based inhibitors of amine oxidases in physiological and medicinal research.

Alkylamino Derivatives of 4-Aminomethylpyridine as Inhibitors of Copper-Containing Amine Oxidases

The first substratelike, reversible inhibitors of different copper amine oxidases (CAOs) with IC50 (M) as low as 2.0 x 10(-8) corresponding to derivatives of 4-aminomethylpyridine with alkoxy (1a-d), alkylthio (2a,b), and alkylamino (3a-e, 4a-j) groups in the positions 3 and 5 have been prepared and studied. The inhibitors 1a-d are active on benzylamine oxidase and semicarbazide-sensitive amine oxidase and are very selective with respect to diamine oxidase, lysyl oxidase, and monoamine oxidases. The inhibitors 2a,b are selective for benzylamine oxidase whereas 2a is also a new type of good substrate of diamine oxidase. The inhibitors 3a-e and 4a-j are substratelike, reversible, nonselective inhibitors of various CAOs including pea seedling amine oxidase and Hansenula polymorpha amine oxidase, whose enzymatic sites are known from X-ray structure determinations. The inhibitors 3b,c and 4b,c are excellent substratelike tools for studies correlating CAOs that afford crystals suitable for X-ray structure determinations with CAOs from mammals.

Synthesis of 4-Aminomethyl-5-ethoxy-3-[(4-vinyl) benzyloxy]pyridine and Its Polymeric Derivatives Planned as Selective Inhibitors of Enzymes

Abstract The synthesis of the new monomer 4-aminomethyl-5-ethoxy-3-[(4-vinyl)benzyloxy]pyridine and its hydrochloride derivative together with their radical homo- and copolymerization to afford the first examples of macromolecular systems planned as selective inhibitors of copper-containing amine oxidases are described.

Stabilization of S-adenosylmethionine decarboxylase by aminoguanidine

Aminoguanidine, an inhibitor of copper-containing amine oxidases, is often used in cell culture studies to prevent the oxidation of added polyamines or their derivatives by the amine oxidase present in bovine serum. However, in the present study, we demonstrate that aminoguanidine, besides affecting the degradation of polyamines, may affect one of the important regulatory enzymes in the biosynthesis of polyamines, namely S-adenosylmethionine decarboxylase (AdoMetDC). Aminoguanidine was shown to induce a 2-3-fold increase in the AdoMetDC levels in L1210 cells. This increase was fully explained by a stabilization of the enzyme, probably caused by the binding of aminoguanidine to the active site of AdoMetDC.

Guanabenz as inhibitor of copper-containing amine oxidases.

The effects of guanabenz on some copper containing amine oxidases are described. Guanabenz 'in vitro' inhibits pig plasma benzylamine oxidase with a IC50 M 5.1 +/- 0.8 X 10(-6) M. It also inhibits pig kidney diamine oxidase and rat liver mitochondrial monoamine oxidase at higher concentrations. The significance of this property of guanabenz is discussed.