Solvent Proton Magnetic Relaxation in Solution of Rabbit Liver Cytochrome P450. On the Corfelation Time for the Electron Proton Dipole-Dipole Interaction

Structural parameters can be derived from PMR measurements if the correlation time fdr the spin interactions is known. The relaxation rates induced by the ferric haem-iron of cyt P450 were found to be frequency independent from 10 to 37 MHz. The possible limits for the correlation time according to Solomon\u27s theory are discussed with regard to the possible existence of a water molecule at the sixth coordination site of the haem-iron. No definite conclusion could be reached in this respect, but the results are definetely in favour of a haem environment which can accomodate several water molecules exchanging quickly with the bulk of solvent