Reaction course of the kinetic resolution of rac- 1-phenyl ethanol. Reaction was performed using a NAD+ regeneration system consisting of 0.2 mg of NOX immobilized on Gx-ag as method described and 4 mg of alcohol dehydrogenase from Thermus thermophilus HB27 immobilized as described elsewhere . The reaction mixture contained 0.5 mM NADH, 7.5 mM rac-1-phenylethanol in 10 mM sodium phosphate at pH 7 and 45 C. Substrate conversion was determined by HPLC as previously described . In the same way, enantiomeric excess (ee) at 50% of conversion was determined by chiral HPLC as previously described . Symbols: acetophenone (empty circles) and 1-(S)-phenylethanol (full squares).