Exploring the Chemical Space of Proluciferins as Probe Substrates for Human Cytochrome P450 Enzymes

We report the synthesis of 21 new proluciferin compounds that bear a small aliphatic ether group connected to the 6' hydroxy function of firefly luciferin and either contain an acid or methyl ester function at the dihydrothiazole ring. Each of these compounds was found to be a substrate for some members of the human CYP1 and CYP3 families; a total of 92 new enzyme-substrate pairs were identified. In a screen of the whole human P450 complement (CYPome) with three selected proluciferin acid substrates, another 13 enzyme-substrate pairs were detected, which involve enzymes belonging to the CYP2, CYP4, CYP7, CYP21, and CYP27 families. All in all, we identified new probe substrates for members of seven out of 18 human CYP families.