I have an in vitro enzymatic reaction produces NAD+ and another molecule, but the two coelute very close to each other on HPLC. I need to isolate the other molecule in large amounts for preparative HPLC, and would like to completely reduce the NAD+ to NADH (which elutes separately from the molecule) so that there is no risk of peak overlap and contamination of my molecule by NAD+. Are there enzymatic or chemical reductants I can use to efficiently and fully scrub the NAD+ to NADH with low risk of reducing the other molecule?