FIGURE 1.

NADPH-dependent carbonyl-reducing activities in crude enzymes prepared from cucumber and Arabidopsis leaves. Activity levels shown in columns were calculated based on a decrease of absorbance at 340 nm of NADPH (6.22 mm⁻¹ cm⁻¹). Specific activity levels for acrolein are set to 100% activity (specific activity levels were 35 ± 6 (cucumber, gray bar) and 11.4 ± 3.4 (Arabidopsis, white bar) nmol/min·mg protein, respectively). Error bar indicates ±S.E. (n = 3). Relative activity for each substrate is shown in the graph. Whether the α,β-unsaturated bond was reduced (+) or not (−) was judged based on the appearance of the corresponding saturated carbonyl after enzymatic reaction by means of HPLC analysis (representative result is shown in inset chromatogram, in which acrolein was partly converted to propionaldehyde).