Amino acid oxygenases

Amino acid oxygenases are internal monooxygenases. They catalyze the following reaction  

Hydroxylation of Tetragonal Carbon Atoms and Oxidative Demethylation 

Hydroxylation of tetragonal carbon atoms by mono oxygenases stereospecifically replaces a hydrogen atom by a hydroxyl group. Nearby hydrogen atoms do not 

The oxidative elimination of 0-methyl and iV-methyl groups is initiated in this way by hydroxylation of the CHg-group. The resulting hydroxy derivatives decompose spontaneously to amino or hydroxy compounds and formaldehyde  

The hydroxylated primary products can be detected only when they are stabilized by glycosylation. 

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Examples of this group of enzymes are the amino acid oxygenases (C 2.6.3). There is great variability in the way hydrogen that is cleaved from the co-substrates is transferred to the oxygenating enzyme. In the simplest cases it is... 

These include the mitochondrial respiratory chain, key enzymes in fatty acid and amino acid oxidation, and the citric acid cycle. Reoxidation of the reduced flavin in oxygenases and mixed-function oxidases proceeds by way of formation of the flavin radical and flavin hydroperoxide, with the intermediate generation of superoxide and perhydroxyl radicals and hydrogen peroxide. Because of this, flavin oxidases make a significant contribution to the total oxidant stress of the body. 

Formation of the 3-hydroxymyristoyl groups of lipid A (Fig. 8-30) requires 02. Comparisons of amino acid sequences suggest that an Fe2+/ 2-oxoglutarate-dependent oxygenase is involved.358 Write a balanced equation for this reaction. 

Degradation of L-arginine by Streptomyces griseus is initiated by a hydroxylase that causes decarboxylation and conversion of the amino acid into an amide (Eq. 24-26), a reaction analogous to that catalyzed by the flavin-dependent lysine oxygenase (Eq. 18-41). The... 

Enzymes that directly incorporate molecular oxygen into organic substrates play a crucial role in many fundamental biological processes such as degradation of natural products in the biosphere, biosynthesis and metabolism of amino acids, hormones, drugs, etc. A wide variety of enzymic oxygenases has been identified and isolated from microorganisms, plants and animals. A detailed description of these enzymes is beyond the scope of this chapter, but several books and review articles are available.1,58-62... 

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