Covalent binding of acetaldehyde selectively inhibits the catalytic activity of lysine-dependent enzymes.

摘要: Hepatic ethanol metabolism generates the reactive intermediate, acetaldehyde, whichbinds to proteins. The binding of acetaldehyde purified enzymes was determined in order ascertain whether such altered their catalytic functions. [14C]Acetaldehyde incubated with alcohol dehydrogenase, glucose-6-phosphate lactate dehydrogenase and RNase A, each at 37°C(pH 7.4). In some reactions, sodium cyanoborohydride included for stabilization Schiff bases, formed as a result reaction between amino groups enzymes. Portions mixture were removed determination ofstable total (stable plus borohydride-reducible) adducts. Alcohol not inhibited by adduct formation. Glucose-6-phosphate RNase, activities which depend on lysine residue sites, dose- time-dependent manner. degree inhibition directly correlated Phosphate, known inhibit active site prevented activity caused These findings indicate thatthe can enzyme activity.