Open AccessSpin Transition of Camphor‐Bound Cytochrome P ‐450
Author(s) -
LANGE Reinhard,
DEBEY Pascale
Publication year - 1979
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1979.tb12916.x
Subject(s) - spin (aerodynamics) , chemistry , camphor , spin states , polyelectrolyte , cytochrome , chemical physics , ionic strength , ionic bonding , proton , ion , inorganic chemistry , organic chemistry , physics , thermodynamics , quantum mechanics , aqueous solution , enzyme , polymer
Variations of the spin state in camphor‐bound cytochrome P ‐450 are interpreted in the light of the polyelectrolyte theory and its implications on the microenvironment of the heme. The ratio of high‐spin to low‐spin iron can serve as a tool to determine the local p a H in the microenvironment of a group (p K 0,app ∼ 5.4) which governs the spin state. The local p a H depends on the electrostatic potential created by negatively charged groups (p K a = 5.6), modulated in turn by p a H and by the screening effect of ionic strength. A model is given for the proton‐coupled spin state change.