All solutions were prepared in 200 mM sodium phosphate buber (NaPi) with 300 mM sodium chloride pH 8.0, unless otherwise stated. The total volume of the reactions was 1 mL and 1.5 mL reaction tubes were used. 20 µM nitroreductase, 1.6 µM BmGDH, 50 mM glucose and 0.5 mM NAD + or NADP + were used. The reaction was started by adding 5 mM substrate from a 10 mM stock solution. Only 1d was added from a 200 mM stock solution in acetonitrile. For solubilization, acetonitrile was added to the reactions to a final concentration of 2.5 % (v/v), and incubated for 24 hours at 25 °C and 1000 rpm. Time samples of 100 µL were taken after 0, 0.5, 1, 2, 4 and 24 hours. The time samples were quenched by adding a spatula of potassium phosphate and then extracting three times with 100 µl ethyl acetate. For substrates 1b-g, 1 mM 1H-indazole was added to the ethyl acetate used as an internal standard. The organic phases were combined and dried over magnesium sulfate before analysis by gas chromatography (GC, see supplementary information).