Mössbauer and EPR Study of Reaction Intermediates of Cytochrome P450

V. Schünemann*, A. X. Trautwein, C. Jung, J. Terner

*Corresponding author for this work
9 Citations (Scopus)


We present a complementary Mössbauer and EPR study on reaction intermediates of substrate-free and substrate-bound cytochrome P450cam from Pseudomonas putida prepared by the freeze-quench method from 57Fe-labeled P450cam using peroxy acetic acid as oxidizing agent. When reacting the substrate-free P450cam for 8 ms reaction time the reaction mixture consists of ∼85% of ferric low-spin iron (Fe(III)) with g-factors and hyperfine parameters of the starting material; the remaining ∼15% are identified as ferryl iron (Fe(IV); SFe=1) by its Mössbauer signature. Parallel to the ferryl iron a tyrosine radical (Srad=1/2) is formed. The two paramagnetic species are not exchange-coupled; however, they are close enough to significantly influence the (EPR) relaxation behavior of the radical spin. In the case of substrate-bound P450cam only trace amounts of the tyrosine radical are formed within 8 ms (<3%); within the accuracy of Mössbauer spectroscopy (5%) iron(IV) can not be detected. The results point to Tyr-96, which is hydrogen-bonded to the substrate camphor, as the candidate for the observed tyrosine radical.

Original languageEnglish
JournalHyperfine Interactions
Issue number1-4
Pages (from-to)279-284
Number of pages6
Publication statusPublished - 28.06.2002


Dive into the research topics of 'Mössbauer and EPR Study of Reaction Intermediates of Cytochrome P450'. Together they form a unique fingerprint.

Cite this