title: Formation of super-reduced Chromatium high-potential iron--sulphur protein in aqueous solution by pulse radiolysis.
abstract: Both the oxidized and reduced forms of Hipip (high-potential iron--sulphur protein) are reduced (approx. 30% yields) by eaq.- in a single-stage process, rate constants 1.7 x 10(10) and 1.8 x 10(10) M-1 . s-1 respectively, at 25 degrees C, pH 7.0 (5 mM-phosphate). Super-reduced Hipip, which is formed in the latter case, has a spectrum which closely resembles that of reduced ferredoxin, i.e. Fe4S4 (SR)4(3-) clusters. The spectrum is stable over 2 s periods investigated. Super-reduced Hipip is reoxidized with O2, rate constant 4.8 x 10(6) M-1 . s-1 at 25 degrees C.
mesh_terms: D002844:Chromatium / Q000032:analysis*; D004583:Electrons; D007506:Iron-Sulfur Proteins; D007700:Kinetics; D008667:Metalloproteins; D010084:Oxidation-Reduction; D010100:Oxygen; D011675:Pulse Radiolysis; D013053:Spectrophotometry; D014867:Water
chemical_list: D007506:Iron-Sulfur Proteins; D008667:Metalloproteins; D014867:Water; D010100:Oxygen