title: Electron self-exchange in Pseudomonas cytochromes.
abstract: Electron self-exchange has been measured by an NMR technique for cytochromes c551 from Pseudomonas aeruginosa and Pseudomonas stutzeri. The rate for P. aeruginosa cyt c551 is 1.2 x 10(7) M-1 s-1 at 40 degrees C in 50 mM phosphate at pH 7. For P. stutzeri, under the same conditions, the rate is 4 x 10(7) M-1 s-1. For both cytochromes, the rate was independent of ionic strength up to 0.5 M in added NaC1, the enthalpy of activation was 20 +/- 4 kcal mol-1, and the entropy of activation was 38 +/- 10 cal mol-1 deg-1.
authors.affiliation: Department of Chemistry, University of Alabama, Tuscaloosa 35487.
authors.forename: R
authors.initials: R
authors.lastname: Timkovich
authors.forename: M L
authors.initials: ML
authors.lastname: Cai
authors.forename: D W
authors.initials: DW
authors.lastname: Dixon
mesh_terms: D001426:Bacterial Proteins; D003574:Cytochrome c Group / Q000378:metabolism*; D004579:Electron Transport; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D009994:Osmolar Concentration; D011549:Pseudomonas / Q000032:analysis*; D011550:Pseudomonas aeruginosa / Q000032:analysis; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D003574:Cytochrome c Group; C017167:cytochrome C(551)