CYP2J2 epoxygenase membrane anchor plays an important role in facilitating electron transfer from CPR

• The N-terminus of CYP2J2 mediates a productive CYP–CPR complex for electron transfer.
• Electron transfer to CYP2J2 is triphasic, indicating multiple conformations possible.
• Association-dependent electron transfer is 200 times slower when CYP2J2 is truncated.

CYP2J2 epoxygenase is a membrane-bound cytochrome P450 primarily expressed in the heart and plays a significant role in cardiovascular diseases. The interactions of CYP2J2 with its redox partner, cytochrome P450 reductase (CPR), and with its substrates are quite complex and can have a significant effect on the kinetics of substrate metabolism. Here we show that the N-terminus of CYP2J2 plays an important role in the formation of CYP–CPR complex for subsequent electron transfer. We demonstrate that when CYP2J2–CPR are pre-incubated before the onset of reduction, the kinetics of reduction is triphasic and is of a similar order of magnitude to previously reported rates in other cytochrome P450 systems. However, when CYP2J2 and CPR form a complex during the time course of the experiment the kinetics of the fastest phase for N-terminus containing full-length CYP2J2 is 200 times faster than the kinetics of reduction of N-terminally truncated CYP2J2. Hence, we show that the N-terminus of CYP2J2 is very important to form a productive CYP–CPR complex to facilitate electron transfer.

Binding kinetics of the formation of Fe(II)–CO peak at 450 nm monitored using stopped flow spectroscopy. The rate of reduction of CYP2J2 by NADPH via CPR depends on the presence of the N-terminus of CYP2J2.Figure optionsDownload as PowerPoint slide