Is chlorzoxazone still a good CYP2E1 probe? A rebuttal says yes
- A recent Supersomes-based paper argued that chlorzoxazone 6-hydroxylation tracks CYP1A1 more than CYP2E1; this article responds to that claim.
- The authors review earlier literature they say was overlooked and conclude the reaction remains an excellent marker of human CYP2E1 activity.
- The stakes are practical: CYP2E1 marker activity is used to evaluate drug interactions.
💡 Points Based on the abstract
Recombinant-enzyme data and human liver data often disagree on probe selectivity, and CYP1A1 is largely an extrahepatic enzyme, so a Supersomes result alone shouldn't overturn a hepatic marker. Before anyone changes a DDI protocol, I'd want a human liver microsome experiment with selective CYP2E1 and CYP1A inhibitors run side by side.