Alcohol dehydrogenase-catalyzed reduction of protein carbonyl derivatives

A simple method for measuring protein carbonyl derivatives is described. The assay is based on the catalytic reduction of protein carbonyl derivatives by NADH-dependent alcohol dehydrogenase at pH 7.5. Bovine serum albumin, oxidized by a system that generates highly reactive hydroxyl radicals via a Fenton-type reaction, is reacted with NADH in the presence of the enzyme. The carbonyl derivatives are quantitated on the basis of absorbance changes at 340 nm using millimolar absorptivity of 6.2 mM-1 cm-1. The method correlates well with a method that utilizes 2,4-dinitrophenylhydrazine.