Simultaneous measurement of CYP1A2 activity, regioselectivity, and coupling: Implications for environmental sensitivity of enzyme-substrate binding

► New method to concurrently monitor CYP1A2 activity, coupling, and regioselectivity. ► CYP1A2 coupling is not affected by temperature or buffer concentration. ► CYP1A2 regioselectivity is not affected by temperature or buffer concentration. ► CYP1A2 selectivity is affected by buffer type and pH.