Inhibitor/fatty acid interactions with cytochrome P‐450 BM3

Abstract
The interaction of fatty acid substrate (palmitate) and inhibitor (metyrapone: 2‐methyl‐1,2‐di‐3‐pyridyl‐1‐propanone) with cytochrome P‐450 BM3 was analysed by UV‐visible and circular dichroism spectroscopy, and by surface‐enhanced resonance Raman scattering (SERRS). While visible spectroscopy provides information on the relative affinities of these compounds, SERRS provides additional novel data indicating palmitate‐induced structural changes in the haem environment. SERRS also demonstrates that binding of both palmitate and the large nitrogenous ligand metyrapone occurs simultaneously to P‐450 BM3 — highlighting the usefulness of this technique in probing haemoprotein active sites.