The metabolism of acetaldehyde in mammalian tissues. Reactions in rat-liver suspensions under aerobic conditions

Publisher Website
Google Scholar
Abstract
When acetaldehyde is added to rat-liver suspensions in KCl-phosphate buffer under aerobic conditions the rate of disappearance of this substance corrected for the part which is reduced to ethanol (the "aldehyde activity") is increased to nearly twice the value found under anaerobic conditions with the same concentration of NAD+ [nicotinamide-adenine-dinucleotide]. Inhibition experiments suggest that the increased "aldehyde activity" is not caused by autotoxidizable flavoproteins. The effect is not abolished by inhibitors of the respiratory chain between NADH [nicotinamide-adenine-dinucleotide reduced form] and cytochrome c, but is strongly diminished by azide. The effect cannot be explained as release of an inhibition by NADH of the aldehyde de-hydrogenation. It is suggested that the increased "aldehyde activity" under aerobic conditions may be caused by the formation of a complex between aldehyde dehydrogenase, microsomal NADH-cytochrome c reductase and NADH, which could be oxidized by cytochrome c. The dissociation of NADH from the aldehyde dehydrogenase, which might be the rate-limiting step, would thus be circumvented.