화학공학소재연구정보센터
Journal of Physical Chemistry A, Vol.102, No.50, 10333-10339, 1998
Proton-assisted electron transfer
The case for highly selective long range "proton assisted" electron transfer in biomolecules (PA-ET), involving the hopping of protons and hydrogen atoms along H-bond chains connecting two redox sites, is discussed and analyzed on systems closely resembling typical biochemical sequences. These systems consist of an electron acceptor, an H-bond/covalent-bridge chain and an electron donor, and monohydroparabenzoquinone as the electron acceptor and a xanthine-like molecule as the electron donor and acceptor species held together by one or more peptide bridges. It is shown that, in biochemical structures, despite the involvement of the imidol (oximine) form of the peptide link, (a) PA-ET is energetically efficient and (b) the rate constants for proton-transfer, which is arguably the rate-controlling step, are reasonably high, the transfer times being on the order of hundreds of picoseconds.