FIGURE 7.

Effects of SOD on GTN denitration (A) and ALDH2 inactivation (B). A, ALDH2 (50 μg/0.1 ml) was incubated for 10 min at 37 °C in 0.2 ml of phosphate buffer (pH 7.4) containing 100 μm [¹⁴C]GTN, 3 mm MgCl₂ in the absence and presence of 2 mm DTT and 1,000 units/ml SOD. 1,2-GDN was extracted and quantified by radio thin layer chromatography as described under “Experimental Procedures.” The data shown are the mean values ± S.E. of three independent experiments. B, GTN-induced inactivation of the dehydrogenase activity of WT-ALDH2 in the absence and presence of SOD (5,000 units/ml). For experimental details see “Experimental Procedures” and Ref. 13. v₀, rate of acetaldehyde oxidation; k_inact, rate of GTN-triggered enzyme inactivation; v_residual, residual dehydrogenase activity of ALDH2 exposed to 50 μm GTN; v_restored, dehydrogenase activity restored by 0.4 mm DTT.