Enhancement of acetaldehyde-protein adduct formation by L-ascorbate.
The effect of L-ascorbate on the binding of [14C]acetaldehyde to bovine serum albumin was examined. In the absence of ascorbate, acetaldehyde reacted with albumin to form both unstable (Schiff bases) and stable adducts. Ascorbate (5 mM) caused a time-dependent increase in the formation of total acetaldehyde-albumin adducts, which were comprised mainly of stable adducts. Significant enhancement of adduct formation by ascorbate was observed at acetaldehyde concentrations as low as 5 microM. An ascorbate concentration as low as 0.5 mM was still effective in stimulating stable adduct formation. The electron acceptor, 2,6 dichlorophenolindophenol, prevented the ascorbate-induced increase in albumin-adduct formation. Ascorbate also caused enhanced acetaldehyde adduct formation with other purified proteins, including cytochrome c and histones, as well as the polyamino acid, poly-L-lysine. These results indicate that ascorbate, acting as a reducing agent, can convert unstable acetaldehyde adducts to stable adducts, and can thereby increase and stabilize the binding of acetaldehyde to proteins.
D015086:2,6-Dichloroindophenol / Q000494:pharmacology; D000079:Acetaldehyde / Q000378:metabolism*; D001205:Ascorbic Acid / Q000494:pharmacology*; D003574:Cytochrome c Group / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D007700:Kinetics; D011107:Polylysine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D012710:Serum Albumin, Bovine / Q000378:metabolism*
D003574:Cytochrome c Group; D006657:Histones; D011107:Polylysine; D012710:Serum Albumin, Bovine; D015086:2,6-Dichloroindophenol; D000079:Acetaldehyde; D001205:Ascorbic Acid