Characterization of xenobiotic reductase A (XenA): study of active site residues, substrate spectrum and stability. 
Xenobiotic reductase A (XenA) has broad catalytic activity and reduces various α,β-unsaturated and nitro compounds with moderate to excellent stereoselectivity.  Single mutants C25G and C25V are able to reduce nitrobenzene, a non-active substrate for the wild type, to produce aniline.  Total turnover is dominated by chemical rather than thermal instability.