A Fourier transform (FT) EPR technique has been used to study the photoinduced electron transfer from zinc-substituted myoglobin (ZnMb) to 1,4-benzoquinone (BQ). Both porphyrin cation and BQ anion radicals (BQ-) were observed, which provide direct evidence of an electron transfer occurring between a porphyrin moiety (ZnPP) in myoglobin and BQ. Electron transfer rate constants, spin-lattice relaxation times of triplet porphyrin and BQ- and magnitudes of chemically induced dynamic electron polarization (CIDEP) due to the triplet mechanism (TM) and the radical pair mechanism (RPM) were evaluated from decay analyses of the FT-EPR signals of BQ-. These results were compared with those for a [5,10,15,20-tetrakis(4-sulfonatophenyl)porphinato]zinc(II) (ZnTPPS)-BQ system and discussed in terms of protein effects in ZnMb. We concluded that electron transfer occurs from the ZnPP moiety to BQ which is located at the surface of myoglobin.
|Number of pages||8|
|Journal||Journal of the Chemical Society - Faraday Transactions|
|Publication status||Published - 1997 Feb 21|
ASJC Scopus subject areas
- Physical and Theoretical Chemistry