Oxygen oxidoreductase

Ubiquitous mitochondrial monoamine oxidase [monoamine oxygen oxidoreductase (deaminating) (flavin-containing) EC 1.4.3.4 MAO] exists in two forms, namely type A and type B [ monoamine oxidase (MAO) A and B]. They are responsible for oxidative deamination of primary, secondary, and tertiary amines, including neurotransmitters, adrenaline, noradrenaline, dopamine (DA), and serotonin and vasoactive amines, such as tyramine and phenylethylamine. Their nonselec-tive and selective inhibitors ( selective MAO-A and -B inhibitors) are employed for the treatment of depressive illness and Parkinson s disease (PD). 

Lipoxygenase (linoleate oxygen oxidoreductase) catalyzes the hydroperoxidation of fatty acids containing a methylene-interrupted conjugated diene system. The degradation of the hydroperoxides results in the formation of numerous secondary products (46-48). 

Polyamine oxidase (amine oxygen oxidoreductase, deaminating, flavin-containing), is also a FAD-dependent enzyme and has many similarities to MAO. It is responsible for the oxidation of the secondary amino group in such substrates as A/-acetyl spermine and spermidine in the biosynthesis of spermidine and putrescine [1,12], This enzyme will not be covered in this chapter. 

ATP [L-tyrosine,tetrahydropteridine oxygen oxidoreductase (3-hydroxylat-ing)] 0-phosphotransferase... 

M. Takahashi, M. Pischetsrieder, and V. M. Monnier, Isolation, purification, and characterization of Amadoriase isoenzymes (fructosyl amine-oxygen oxidoreductase EC 1.5.3) from Aspergillus sp, J. Biol. Chem., 1997, 272, 3437-3443. 

The shell precursors in the vitelline cells - proteins, phenols and phenol oxidase (EC 1.14.18.1, monophenol o-diphenol oxygen oxidoreductase) - can all be stained specifically with cytochemical reagents although the reactions are not as intense as in trematodes (810). The most useful of these reagents are probably (a) Fast Red Salt B, which stains phenolic materials orange/purple, and (b) catechol, which can be used for detecting the phenol oxidase. Details of these techniques are given by Smyth (789). 

Lower primates and mammals other than humans carry purine metabolism one step further with the formation of aUantoin from uric acid, a step mediated by uricase ([urate oxygen] oxidoreductase, EC 1.7.3.3). In humans, approximately 75% of uric acid excreted is lost in the urine most of the remainder is secreted mto the gastrointestinal tract, where it is degraded to allantoin and other compounds by bacterial enzymes. 

System of microsomal MO comprises three main catalytic components. Cytochrome P450 system (reduced flavoprotein oxygen oxidoreductase, EC 1.14.14.1) participate in hydroxylation reactions through processes of oxidoreduction. In oxidative reactions very important is the presence of oxygen, while in reduction reactions electrons are transferred from heme. In some of these reactions enzyme NADPH-P450 reductase (NADPH fcrricytochromc oxidoreduc-... 

Complex heme proteins which contain redox centers other than just electron transfer hemes are normally associated with enzymatic catalysis. In this section, we will refer to some of the best studied complex heme proteins sulfite reductase, nitrite reductase, formate dehydrogenase, fumarate reductase and rubredoxin-oxygen oxidoreductase. 

AiiA-like protein Bascillus thurlngiensis Beta-lactamase type II Bacteroides fragilis Rvibredoxin-oxygen oxidoreductase Desulfovibrio glgas... 

A new member of the family of nonheme diiron enzymes recently discovered is called rubrerythrin. This metalloprotein is formally classified as an oxidoreductase (rubredoxin oxygen oxidoreductase). The diiron(III,III) active site structure is displayed in Figure 2(f). This biomolecule possesses two histidines coordinated to one iron and one histidine coordinated to the second iron. A carboxylate bridges the two irons and there are carboxylate ligands also coordinated to each iron. The purpose of this enzyme in the strict anaerobe is to safely reduce oxygen to water. 

ACP = acyl carrier protein ACPA D = ACPA desat-urase AlkB = octane 1-monooxygenase AOX = alternative oxidase DMQ hydroxylase = 5-demethoxyquinone hydroxylase EXAFS = extended X-ray absorption fine structure spectroscopy FMN = flavin mononucleotide FprA = flavoprotein A (flavo-diiron enzyme homologue) Hr = hemerythrin MCD = magnetic circular dichroism MME hydroxylase = Mg-protophorphyrin IX monomethyl ester hydroxylase MMO = methane monooxygenase MMOH = hydroxylase component of MMO NADH = reduced nicotinamide adenine dinucleotide PAPs = purple acid phosphatases PCET = proton-coupled electron transfer, PTOX = plastid terminal oxidase R2 = ribonucleotide reductase R2 subunit Rbr = rubrerythrin RFQ = rapid freeze-quench RNR = ribonucleotide reductase ROO = rubredoxin oxygen oxidoreductase XylM = xylene monooxygenase. 

Lipoxygenases (EC 1.13.11.12, linoleate oxygen oxidoreductase) are found in many plants with soybeans having the highest activity. The characteristics of these enzymes were reviewed recently (Robinson et al., 1995 Gardner, 2003). Fujimaki et al. (1965) showed that lipoxygenase was associated with hexanal production in soybeans. 

In further consideration of the biosynthesis of the piperidine alkaloids the question of the significance of the incorporation of cadaverine must be answered. Accordingly further research has been directed to this point and it has been shown that cadaverine is a normal component of S. acre, that it is a specific precursor of sedamine (20), and that it is formed from lysine at the same time as sedamine. It follows then that any scheme for the biosynthesis of the piperidine alkaloids which does not accommodate cadaverine as a normal component is unrealistic An eminently reasonable hypothesis which fits all the evidence is shown in Scheme 1 it was anticipated in last year s Report. For those alkaloids derived from lysine without the intervention of a symmetrical intermediate, cadaverine formed by decarboxylation of lysine must remain enzyme-bound and therefore unsymmetrical. Exogenous cadaverine enters the pathway at this point by absorption on to the enzyme to give (29). In order to explain the incorporation of lysine into some alkaloids by way of a symmetrization step it is necessary only to postulate equilibration of bound with unbound cadaverine. The proposal that pyridoxal phosphate is involved in this pathway is more than mechanistically attractive, for L-lysinedecarboxylase (EC 4.1.1.18, L-lysine carboxy-lyase) and diamine oxidase [EC 1.4.3.6, diamine oxygen oxidoreductase (deaminating)], the two enzymes whose participation in the conversion of lysine into A -piperideine (30) is likely, both require pyridoxal phosphate as a co-factor. 

A rather widely occurring enzyme which catalyzes the oxidation of uric acid is uricase (urate oxygen oxidoreductase, EC 1.7.3.3). This enzyme is highly selective for uric acid and, except under ususual circumstances, it catalyzes the conversion of uric acid to allantoin (18). The absence of uricase... 

Schauer, R. (1970b) Biosynthesis of N-glycolylneuraminic acid by an Ascorbate or NADPH-dependent, N-acetyl hydroxylating N-acetylneuraminate Oxygen Oxidoreductase in Homogenates of the Porcine Submaxillary Gland , Hoppe-Seyler s Zeitschrift fur Physiologische Chemie, 351, 783-91... 

Lipoxygenase (linoleate oxygen oxidoreductase, EC 1.13.11,12) is a term applied to a group of enzymes which catalyse the oxygenation, by molecular oxygen, of fatty acids containing a cw, cw-1, 4-pentadiene system to produce conjugated hydroperoxydiene derivatives (see also Section 10.3) ... 

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