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Compressibility and uncoupling of cytochrome P450cam: high pressure FTIR and activity studies

Item Type:Article
Title:Compressibility and uncoupling of cytochrome P450cam: high pressure FTIR and activity studies
Creators Name:Jung, C. and Kozin, S.A. and Canny, B. and Chervin, J.C. and Hoa, G.H.
Abstract:The effect of the hydrostatic pressure on the CO ligand stretch vibration in cytochrome P450cam-CO bound with various substrates is studied by FTIR. The vibration frequency is linearily shifted to lower values with increasing pressure. The slope of the shift gives the isothermal compressibility of the heme pocket and is found to be related to the high-spin state content in an opposite direction to that previously observed from the pressure-induced shift of the Soret band. This opposite behaviour is explained by the dual effect of heme pocket water molecules both on the CO ligand and on electrostatic potentials produced by the protein at the distal side. The latter effect disturbs ligand-distal side contacts which are needed for a specific proton transfer in oxygen activation when dioxygen is the ligand. Their loss results in uncoupled H2O2 formation.
Keywords:CO Stretch Mode, Compressibility, Cytochrome P450, FTIR, Uncoupling
Source:Biochemical and Biophysical Research Communications
Publisher:Academic Press (U.S.A.)
Page Range:197-203
Date:5 December 2003
Official Publication:https://doi.org/10.1016/j.bbrc.2003.09.164
PubMed:View item in PubMed

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