Oxidative deamination is a form ofdeamination that generatesα-keto acids and other oxidized products from amine-containing compounds, and occurs primarily in theliver.[1] Oxidative deamination is stereospecific, meaning it contains different stereoisomers as reactants and products; this process is either catalyzed by L or D- amino acid oxidase and L-amino acid oxidase is present only in the liver and kidney.[2] Oxidative deamination is an important step in the catabolism of amino acids, generating a more metabolizable form of the amino acid, and also generatingammonia as a toxic byproduct. The ammonia generated in this process can then be neutralized intourea via theurea cycle.
Much of the oxidative deamination occurring in cells involves the amino acidglutamate, which can be oxidatively deaminated by the enzymeglutamate dehydrogenase (GDH), usingNAD orNADP as acoenzyme. This reaction generatesα-ketoglutarate (α-KG) and ammonia. Glutamate can then be regenerated from α-KG via the action oftransaminases or aminotransferase, which catalyze the transfer of an amino group from an amino acid to an α-keto acid. In this manner, an amino acid can transfer its amine group to glutamate, after which GDH can then liberate ammonia via oxidative deamination. This is a common pathway during amino acid catabolism.[3]
Another enzyme responsible for oxidative deamination ismonoamine oxidase, which catalyzes the deamination of monoamines via addition of oxygen. This generates the corresponding ketone- or aldehyde-containing form of the molecule, and generates ammonia. Monoamine oxidases MAO-A and MAO-B play vital roles in the degradation and inactivation ofmonoamine neurotransmitters such asserotonin andepinephrine.[4] Monoamine oxidases are important drug targets, targeted byMAO inhibitors (MAOIs) such asselegiline. Glutamate dehydrogenase play an important role in oxidative deamination.
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