Free Radical Transfer Involving Sulphur Peptide Functions
Many biological processes involve series of electron transfer reactions through protein assemblies. Examples of such controlled biological electron transfer chains are the oxidative phosphorylation in mitochondria, and the photosynthesis in chloroplasts. Sulphur peptide functions commonly serve to stabilize, by disulphide bonds, the three-dimensional protein structure, and to hold certain reaction centers in position; for instance, in ferricytochrome c the active heme group is covalently bound by two cysteines and additional coordinative binding of the central iron is provided by a methionine and a histidine group, and in plastocyanine (an electron transfer protein in photosynthesis) the active Cu(II) center involves one cysteine, one methionine and two histidines as ligands. The specific structures of electron transfer proteins, and particularly the environment around the active sites, are thought to play a pertinent role in directing the electron transfer process, and various possible mechanisms of electron transfer through the protein matrix have been discussed.
KeywordsElectron Transfer Pulse Radiolysis Radical Transfer Electron Transfer Protein Sulphur Peptide
Unable to display preview. Download preview PDF.
- 4.R.V. Bensasson, E.J. Land, and T.G. Truscott, “Flash Photolysis and Pulse Radiolysis”, Pergamon Press, Oxford (1983).Google Scholar
- 6.W.A. Prütz, in: “Radiation Research”, Vol. 2 (8th International Congress of Radiation Research, Edinburgh), E.M. Fielden, J.F. Fowler, J.H. Hendry, and D. Scott, eds., Taylor & Francis, London, p. 134 ff. (1987).Google Scholar
- 9.K. Bobrowski, K.L. Wierzchowski, J. Holcman, and M. Ciurak, Studia biophys. 122: 23 (1987).Google Scholar