2.5 General experimental procedure for ERs catalytic reduction
of intermediates (2a-k→3a–k)
A 2 mL microcentrifuge tube, was charged with solvent (1 mL), 10 mM
(2a-k), NAD(P)H (0.1 mM), ERs (0.8 mg mL-1), sodium phosphate buffer (50
mM, pH 7), Incubate at 25 °C for 5 minutes, then The reducing activity
was determined by measuring the decrease of NAD(P)H at 340 nm.