On internal electron transfer in xanthine oxidase.
The structural basis for intramolecular electron transfer in xanthine oxidase (EC 1.2.3.2) has been probed using temperature-jump perturbation and optical spectroscopic methods. Redox equilibria were found to be temperature-insensitive; hence it is argued that electron transfer is not accompanied by any extensive macromolecular conformational changes. No evidence for absorption phenomena ascribable to optical electron transfer could be found throughout the course of reductive titration of the biological particle. The combined results suggest that long-range electron transfer in the xanthine oxidase can best be described as occurring between only weakly interacting redox sites embedded in a rigid protein matrix.
D000818:Animals; D002417:Cattle; D004579:Electron Transport; D007700:Kinetics; D008892:Milk / Q000201:enzymology; D010084:Oxidation-Reduction; D013055:Spectrophotometry, Infrared; D013696:Temperature; D014969:Xanthine Oxidase
D014969:Xanthine Oxidase