V.D.Lakhno, G.N.Chuev, M.N.Ustinin.
Electron Transfer between Globular Proteins: Estimation of the Matrix Element //Biophysics, 1998, v.43, №6, p.901-903

      The dependence of the matrix element of probability of interprotein electron transfer on the mutual orientation of the donor and acceptor centers and on the distance between them was calculated. The calculation was performed under the assumption that the main channel for this process is the electron transfer via collective excitation of a polaron nature, similar to electron solvation. The results obtained agree with the experimental data and indicate a nonexponential behavior of this dependence at transfer distances shorter than 20 angstrem.