FIGURE 6.

Scavenging of NO and hydroethidine oxidation by ALDH2/GTN. A, purified sGC was incubated for 10 min as described in the legend to Fig. 2 with WT- or E268Q-ALDH2 (25 μg each) in the presence of 1 μm DEA/NO. GTN (0.1 mm) and SOD (1,000 units/ml) were present as indicated. The samples were analyzed for [³²P]cGMP as described under “Experimental Procedures.” The data (mean values ± S.E.; n = 3) are expressed as percentages of maximally NO-stimulated sGC activity. B, purified proteins (0.45 mg each) were incubated at 37 °C in 0.7 ml of 50 mm TEA buffer (pH 7.4), containing 3 mm MgCl₂, 0.1 mm DTPA, 2 mm DTT, 2.5 μm hydroethidine, and, where indicated, 0.1 mm GTN, 10 mm chloral hydrate (CH), and 1000 units/ml SOD. Fluorescence was monitored at excitation and emission wavelengths of 490 nm (slit width, 5 nm) and 585 nm (slit width, 20 nm), respectively. The data are the mean values ± S.E. of the increase in fluorescence read-outs (arbitrary units) monitored over 5 min in three to six independent experiments.