Microsomal ethanol oxidation in the colonic mucosa of the rat. Effect of chronic ethanol ingestion.
A microsomal ethanol oxidizing system (MEOS) is present in the colonic mucosa of the rat. This MEOS metabolizes ethanol to acetaldehyde at the physiological pH of 7.4. Alcohol dehydrogenase or catalase are not involved in the reaction. The Michaelis Menten constant of the reaction is 13.7 +/- 0.3 mM and the maximal velocity is 219 +/- 30 pmoles acetaldehyde/mg microsomal protein X min. Bacterial ethanol metabolism does not contribute to the acetaldehyde production in the colonic MEOS. Chronic ethanol consumption has no effect on colonic MEOS activity. In addition, chronic ethanol ingestion does not affect colonic microsomal NADPH-cytochrome-c-reductase nor benzo(a) pyrene hydroxylase activity.
D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000818:Animals; D003106:Colon / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008861:Microsomes / Q000201:enzymology; D009249:NADP / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains
D000431:Ethanol; D009249:NADP; D000429:Alcohol Oxidoreductases; D009251:NADPH-Ferrihemoprotein Reductase