Alcohol dehydrogenase aldehyde dehydrogenases

Alcohol is metabolized by the catalytic action of alcohol dehydrogenase, aldehyde dehydrogenase, and the ethanol-oxidizing system of the endoplasmic reticu-... 

Oxidation Cytochrome P450 Flavin-containing monooxygenase Alcohol dehydrogenase Aldehyde dehydrogenase Monoamine oxidase HaOa-dependent peroxidase... 

Over 90% of alcohol in the plasma is metabolized in the liver by three enzyme systems that operate within the hepatocyte. The remainder is excreted by the lungs and in urine and sweat. Alcohol is metabolized to acetaldehyde by alcohol dehydrogenase in the cell. In turn, acetaldehyde is metabolized to carbon dioxide and water by the enzyme aldehyde dehydrogenase. A second pathway for oxidation of alcohol uses catalase, an enzyme located in the peroxisomes and microsomes. The third enzyme system, the microsomal alcohol oxidase system, has a role in the oxidation of alcohol to acetaldehyde. These last two mechanisms are of lesser importance than the alcohol dehydrogenase-aldehyde dehydrogenase system. 

Besides the monooxygenases discussed above, a number of other oxidoreductases can oxidize xenobiotics. These enzymes are mostly but not exclusively nonmicrosomal, being present in the cytosol or mitochondria of the liver and extrahepatic tissues. The list includes alcohol dehydrogenases, aldehyde dehydrogenases, dihydrodiol dehydrogenases, haemoglobin, monoamine oxidases, xanthine oxidase and aldehyde oxidase. Some of these enzyme systems are discussed below. 

Cytochrome P450 Alcohol dehydrogenase Aldehyde dehydrogenase Aldehyde oxidase Carboxylesterase Aiylesterase Acetylesterase Aryl 4-hydroxylase Aryl sulphatase... 

Enzymes catalysing reductions are also found in liver microsomes, e.g. azo-benzene reductase and nitroreductase. Oxidation reactions, which are not due to cytochrome P-450 are catalysed by hexahydrobenzoate dehydrogenase, alcohol dehydrogenase, aldehyde dehydrogenase, xanthine oxidase, and aldehyde oxidase. Several amines are oxidised by monoamine oxidase or diamine oxidase. 

Abstract Acetic acid bacteria (AAB) are obligate aerobes that belong to the a-Proteobacteria and are used for industrial vinegar production because of then-remarkable ability to oxidize ethanol by alcohol dehydrogenase, aldehyde dehydrogenase, and terminal oxidase of respiratory chain members on the ceU membrane. Acetic acid tolerance is a crucial abiUty allowing AAB to stably produce large amounts of acetic acid. 

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