Membrane environment drives cytochrome P450's spin transition and its interaction with cytochrome b5.

Heme's spin-multiplicity is key in determining the enzymatic function of cytochrome P450 (cytP450). The origin of the low-spin state in ferric P450 is still under debate. Here, we report the first experimental demonstration of P450's membrane interaction altering its spin equilibrium which is accompanied by a stronger affinity for cytochrome b₅. These results highlight the importance of lipid membrane for the function of P450. [ABSTRACT FROM AUTHOR]