title: ESR studies on iron-sulfur clusters of complex II in Ascaris suum mitochondria which exhibits strong fumarate reductase activity.
abstract: Complex II of Ascaris suum mitochondria, which functions as fumarate reductase in physiological conditions, contains three types of iron-sulfur clusters. These correspond to clusters S-1, S-2 and S-3 and are distinguishable by low-temperature ESR studies. Cluster S-1 is reduced by succinate, giving ESR signals with gz, gy and gx values at 2.033, 1.939 and 1.920. The existence of cluster S-2 is suggested by an enhancement of the S-1 spin relaxation induced upon reduction of S-2 by dithionite. Cluster S-3 is ESR detectable under air-oxidized conditions and gives a strong signal at g = 2.025. Cluster S-3 was only partially reduced even with an excess amount of sodium succinate, which is a common characteristic of fumarate reductase but this is not seen in the mitochondrial complex II.
authors.affiliation: Department of Biology, Faculty of Science, University of Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Hata-Tanaka
authors.forename: K
authors.initials: K
authors.lastname: Kita
authors.forename: R
authors.initials: R
authors.lastname: Furushima
authors.forename: H
authors.initials: H
authors.lastname: Oya
authors.forename: S
authors.initials: S
authors.lastname: Itoh
mesh_terms: D000818:Animals; D001200:Ascaris / Q000201:enzymology* / Q000648:ultrastructure; D004227:Dithionite; D004578:Electron Spin Resonance Spectroscopy; D042963:Electron Transport Complex II; D007506:Iron-Sulfur Proteins; D008667:Metalloproteins; D008872:Microwaves; D008928:Mitochondria / Q000201:enzymology*; D009097:Multienzyme Complexes / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D013385:Succinate Dehydrogenase / Q000378:metabolism*; D013386:Succinates; D019802:Succinic Acid
chemical_list: D007506:Iron-Sulfur Proteins; D008667:Metalloproteins; D009097:Multienzyme Complexes; D013386:Succinates; D004227:Dithionite; D019802:Succinic Acid; D010088:Oxidoreductases; D042963:Electron Transport Complex II; D013385:Succinate Dehydrogenase