Figure 3.

Epimerase activity of the epimerase domain, but not the PPOX domain, of the Arabidopsis NAD(P)HX epimerase-PPOX protein. Assays contained 25 mm Tris-HCl, pH 9.0, 1 mm KCl, NADHX preparations enriched in (S)-NADHX (1 mm; A) or (R)-NADHX (0.5 mm; B), and 10 µg of the separate epimerase (Epm) or PPOX domains. Incubation was at 30°C for 10 min. Controls without enzyme (no Enz) were included. Reactions were analyzed by HPLC, monitoring A₂₇₉. Peak fronts of (S)- and (R)-NADHX are marked by dashed lines.