Aldol-proteins formation in the NADPH-dependent microsomal peroxidation. The products of catalyzed microsomal peroxidation increase the absorbance of the control sample at 266 nm by a factor of more than 14 (Bars #1 vs. #3). When sodium bisulfite was added at the end of the incubation period of peroxidation, the absorbance fell (Figure 3, #4), and reached values close to its control. Even in the control case, a fall of the initial amount could be observed with the addition of bisulfite (Bars #1 vs. #2). Bisulfite interferes directly with carbonyl groups derived from aldehydes in the aldolic condensation. * p < 0.01; **p < 0.0001 compared with all the other groups.