Can a single oxidant with two spin states masquerade as two different oxidants? A study of the sulfoxidation mechanism by cytochrome p450.
Density functional calculations were performed on the sulfoxidation reaction by a model compound I (Cpd I) of cytochrome P450. By contrast to previous alkane hydroxylation studies, which exhibit a dominant low-spin (LS) pathway, the sulfoxidation follows a dominant high-spin (HS) reaction. Thus, competing hydroxylation and sulfoxidation processes as observed for instance by Jones et al. (Volz, T. J.; Rock, D. A.; Jones, J. P. J. Am. Chem. Soc. 2002, 124, 9724) are the result of a two-state reactivity scenario, whereby the hydroxylation originates from the LS pathway and the sulfoxidation from the HS pathway. In this manner, two spin states of a single oxidant (Cpd I) can be disguised as two different oxidants. The calculations rule out the possibility that a second oxidant (the ferric peroxide, Cpd 0 species) interferes in the observed results of Jones et al.
Sharma
Pankaz K
PK
Department of Organic Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram 91904, Jerusalem, Israel.
De Visser
Samuël P
SP
Shaik
Sason
S
D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000378:metabolism; D058085:Iron Compounds / Q000737:chemistry; D016877:Oxidants / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry; D013454:Sulfoxides / Q000737:chemistry*; D013816:Thermodynamics
D058085:Iron Compounds; D016877:Oxidants; D011166:Porphyrins; D013454:Sulfoxides; D003577:Cytochrome P-450 Enzyme System