The pro-luciferin substrates can be used to monitor the activity of specific isoforms of cytochrome P450 or NAT2 as indicated in the name of the substrate. The Luciferin-MultiCYP is a promiscuous substrate that reacts with at least 21 P450 isoforms and is useful for measuring net CYP activity in a mixed population of P450s. The Luciferin-NAT2 is an excellent substrate for N-acetyltransferase 2 (NAT2), a phase II biotransformation enzyme that acetylates aromatic amine groups on xenobiotic compounds. This substrate shows little to no cross-reactivity with NAT1.|