Amines Oxidases

Amine oxidases catalyze the transformation of amines and molecular oxygen to aldehydes, ammonia, and HgOg  

They also react with monomethylated amines to form methylamine (D 9.2). Mono-, di- and polyamine oxidases may be distinguished according to the preferred substrate. The substrate specificity of the enzymes, however, is relatively low. 

The oxidation of chiral amines represents a fundamental key step in various physiological processes, being important, for example, for detoxification, cell growth, and signaling. AOs are the enzymes responsible for this particular transformation. These 

Simplified reaction scheme for the oxidation of an amine to the corresponding imine through FAD-containing amine oxidases (AOs). 

Redox cycle of the cofactor for flavin-containing enzymes. 

In addition to liver aldehyde dehydrogenase, a number of other enzymes present in the soluble fraction of liver homogenates will oxidize aldehydes and certain N-heterocyclic compounds. Among these are aldehyde oxidase and xanthine oxidase (see below), both flavoprotein enzymes containing molybdenum. These enzymes catalyze the oxidation of aldehydes formed by the deamination of endogenous amines by amine oxidases. 

Fe2+ to generate an enzyme-bound iron-oxygen complex, and ascorbic acid (vitamin C) to subsequently reduce this complex. 

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Copper amine oxidases structure and function. B. Mondovi and P. Riccio, Adv. Inorg. Biochem., 1984, 6, 225 (116). 

Figure 13.4 Histamine synthesis, metabolism and receptors. Current knowledge does not justify presentation of a schematic histaminergic synapse. (1) Histidine decarboxylase (2) histamine-A-methyltransferase (3) mono amine oxidase (MAOb)...

Hacisalihoglu A, JA Jongejan, JA Duine (1997) Distribution of amine oxidases and amine dehydrogenases in bacteria grown on primary amines and characterization of the amine oxidase from Klebsiella oxytoca. Microbiology (UK) 143 505-512. 

Cooper RA, PE Knowles, DE Brown, MA McGuirl, DM Dooley (1992) Evidence for copper and 3,4,6-trihy-droxyphenylalanine quinone cofactor as an amine oxidase from Gram-negative Escherichia coli K-12. Biochem J 288 337-340. 

Divalent Co substitution in copper amine oxidase revealed 19% of the native specific activity (for MeNH2) and 75% of the native reactivity toward phenylhydrazine. The major cause of this was a 68-fold increase in Km for 02. These investigations support the idea that electrons flow directly to bound 02 without the need for a prior metal reduction and that the Cu does not redox cycle but simply provides electrostatic stabilization during reduction of 02 to 02-. 1211... 

Several lupin alkaloids have been derived from the unsaturated quinalozidine 433, that was obtained in the treatment of amine 431 with ortho-quinone 432. This quinone behaves as a model of topaquinone, the cofactor of copper-containing amine oxidases. The cyclization step involved a nucleophilic attack of the piperidine nitrogen of 431 onto a side-chain aldehyde function that is unmasked by the oxidative deamination. Quinolizine 433, when treated with dehydropiperidine, gave the oxime ether 434 that, on ozonolysis followed by reduction, afforded sparteine 10, presumably via the bis(iminium) system 435 (Scheme 102) <1996JOC5581>. 

Nonblue oxidases Amine oxidase Diamine oxidases Galactose oxidase Cytochrome c oxidase... 

Little work has been done in this area. Clark et al. (36), however, reported that mescaline is more extensively deaminated by a soluble rabbit liver amine oxidase preparation than is 2,4,5-trimethoxyphenethylamine. One should also note that the addition of the alpha-methyl will increase the octanol-water partition... 

Semicarbazide Sensitive Amine Oxidase and Vascular Adhesion Protein-1 One Protein Being Validated as a Therapeutic Target for Inflammatory Diseases... 

Molecular Biology of the Copper-Containing Amine Oxidase... 

The natural ligand for the amine oxidase activity is not known for certain. While SSAO/VAP-1 will oxidize endogenous molecules such as methylamine and tyramine, the substrates associated with diapedesis are unknown. It has been speculated that leukocyte cell surface lysine residues or amino sugars, such as mannosamine residues (5) known to be associated with cell/cell recognition may be involved [14,15]. 

ABP1 Amiloride binding protein 1 (amine oxidase (copper-containing)) ABP, DAO, 7q34 - 7q36 KAO, AOC1, DAOl 150,180,506 -150,189,312 8807 5 2428 751... 

AOC-2 Amine oxidase, copper-containing 2 (retina-specific) DA02, 17q21 RAO 38,250,135 -38,256,250 6116 4 2665 2584 (2 isoforms) 757 730... 

AOC-3 Amine oxidase, copper-containing 3 (vascular adhesion protein 1) HPAO, 17q21 SSAO, VAP1, VAP-1, 38,256,727 -38,263, 667 6941 4 4026 763... 

Semicarbazide Sensitive Amine Oxidase and Vascular Adhesion Protein-1... 

MOLECULAR BIOLOGY OF THE COPPER-CONTAINING AMINE OXIDASE FAMILY... 

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