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Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A succinic dehydrogenase (SDH) complex has been purified from Triton X-100-solubilized membranes from Bacillus subtilis by precipitation with specific antibody. Radioactively labeled precipitated complex was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography of the gels. The complex contained equimolar amounts of three polypeptides with approximate molecular weights of 65,000, 28,000, and 19,000. Five succinic dehydrogenase-negative mutants, belonging to the citF group, contained the 65,000-dalton polypeptide in a soluble form in the cytoplasm. Each 65,000-dalton polypeptide had about one molecule of flavin bound. Another citF mutant, citF11, which lacks the 65,000-dalton polypeptide, contained a membrane-bound 28,000-dalton polypeptide. The wild-type succinic dehydrogenase complex contained cytochrome, probably a cytochrome b. The 19,000-dalton polypeptide is suggested to represent the apoprotein of this cytochrome. The 65,000-dalton and the 28,000-dalton polypeptides are thought to constitute succinic dehydrogenase and to correspond to the flavoprotein and the ironprotein, respectively, as described for succinic dehydrogenase isolated from beef heart mitochondria or Rhodospirillum rubrum chromatophores. The results presented suggest that in B. subtilis succinic dehydrogenase is attached to a cytochrome b in the membrane via the 28,000-dalton (ironprotein) polypeptide.
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PMID:Characterization of a succinate dehydrogenase complex solubilized from the cytoplasmic membrane of Bacillus subtilis with the nonionic detergent Triton X-100. 10 58

A 5-aminolevulinic acid-requiring mutant of Bacillus subtilis was isolated. When the mutant is shifted from medium containing 5-aminolevulinic acid to medium lacking this growth factor, the bacteria continued to grow at undiminished rate for about three generations. The membranes from these bacteria contained severely reduced amounts of cytochrome. The mutant was used to study the role of heme synthesis on synthesis and membrane binding of succinic dehydrogenase (SDH). The amount of SDH in whole-cell lysates in the soluble cytoplasmic fraction and in membranes was determined by one-dimensional (rocket) immunoelectrophoresis with an SDH-specific antiserum. After heme synthesis was blocked, the relative amount of SDH in the membrane decreased, whereas increasing amounts of SDH antigen were found in the cytoplasm. When heme synthesis was resumed on readdition of 5-aminolevulinic acid, the amount of membrane-bound SDH antigen increased at a much faster rate than net synthesis. During a 3-h growth period without 5-aminolevulinic acid, there was little change in the pattern of membrane proteins as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of radioactively labeled membranes, as compared to membranes from control cultures. However, both the 65,000-dalton and the 28,000-dalton polypeptides of the SDH complex (L. Hederstedt, E. Holmgren, and L. Rutberg, J. Bacteriol. 138:370-376, 1979) were present in decreasing amounts in membranes from 5-aminolevulinic acid-starved bacteria. From these results we suggest that SDH in B. subtilis is synthesized as a soluble protein and becomes membrane bound only when it attaches to a site in the membrane, (part of) which is a cytochrome of b type.
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PMID:Role of heme in synthesis and membrane binding of succinic dehydrogenase in Bacillus subtilis. 10 59

Extensively or completely activated preparations of beef heart succinate dehydrogenase have been investigated by electron paramagnetic resonance (EPR) techniques at 6 to 97 K. Reductive titrations with dithionite and rapid kinetic studies were performed with various types of soluble and membrane-bound preparations of the enzyme. The following components were detected and their behavior analyzed: a free radical, presumably arising from the covalently bound flavin on reduction, two iron-sulfur centers of the ferredoxin type, the signals of which appear on reduction, and a highpotential iron-sulfur component, detectable in the oxidized state. The high-potential component was only detected in complex II and inner-membrane preparations. This component and one of the ferredoxin-type centers were present in amounts close to stoichiometric with the flavin and were reduced by substrate. The other ferredoxin-type center was present in amounts between 0.1 and 0.5 times that of the flavin and was reduced only by dithionite. Of the components reduced by succinate, however, only a fraction (up to 50% of the high-potential iron-sulfur center and 40-60% of the ferredoxin-type iron-sulfur center) was reduced within the turnover time of the enzymes; In complex II not more than about 10% of the flavin appeared in the semiquinone form at any time. Soluble, purified preparations behaved similarly except that the high-potential component was nearly or completely absent and extensive accumulation of the free radical occurred (up to 70 to 80% of the flavin) in titration and kinetic experiments. No significant difference was observed between the rates of semiquinone formation and the reduction of the ferredoxin-type or high-potential centers by the substrate. Also no qualitative differences in the properties studied in this work became apparent between prepatations containing 4 or 8 iron atoms, respectively.
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PMID:Iron-sulfur components of succinate dehydrogenase: stoichiometry and kinetic behavior in activated preparations. 16 76

1. The membrane-bound succinoxidase of Escherichia coli was fractionated with deoxycholate into three soluble components, viz. succinate dehydrogenase.cytochrome b1 complex, cytochrome oxidase complex, and a factor identified as a phospholipid-containing component. 2. The dehydrogenase and cytochrome oxidase complexes were partially purified by filtration on Amicon membranes, Sepharose 4B chromatography, and sucrose gradient centrifugation. 3. Reconstitution of membranous succinoxidase, which catalyzes the oxidation of succinate by molecular oxygen by an integrated CN(-)-sensitive pathway, was achieved by mixing the soluble succinate dehydrogenase.cytochrome b1 complex with the soluble cytochrome oxidase complex in the presence of deoxycholate and then removing the detergent by gel filtration on Sephadex G-75. The phospholipid-containing factor stimulated the formation of succinoxidase by about 100% over that observed with the two complexes. 4. Isopycnic sucrose gradient centrifugation of succinate dehydrogenase.cytochrome b1 complex, cytochrome oxidase, and the reconstituted succinoxidase gave buoyant densities (p value) as 1.167, 1.229, and 1.194, respectively. 5. Electron microscopic evidence is presented for the vesicular nature of the reconstituted succinoxidase.
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PMID:Reconstitution of escherichia coli succinoxidase from soluble components. 21 41

Aging has recently been shown to promote lipid peroxidation of mitochondrial membranes by a mechanism involving chaotropic oxidants (5). The present paper reports on the relationship between these membrane alterations and the activities of lipid-dependent enzymes of isolated heart mitochondria from 3 month and 24 month old rats. 1. Temperature breaks of Arrhenius plots reveal age-dependent shifts to higher temperatures for the succinate oxidase system (delta t = 1,7 degrees C), the beta-hydroxybutyrate dehydrogenase, the succinate dehydrogenase and the ATP-ase (delta t = 3,0 degrees C). 2. Specific activities of the above enzymes are distinctly lowered in preparation from aged rats. 3. Thermotropic differences of the particular enzyme activities completely disappeared after solubilization of the lipid components by Triton X-100. 4. ESR studies exhibit a clear decrease in the fluidity of membrane lipids as a function of age. 5. Analysis of the membrane lipids by gas-liquid chromatography reveals a distinct age-dependent fall in the content of polyunsaturated fatty acids accompanied by a slow increase in the degree of fatty acid saturation. 6. It is concluded from the results that aging influences enzyme-protein-lipid interactions by radical-induced peroxidation of the surrounding membrane lipids, but does not affect the intrinsic properties of the membrane-bound enzymes themselves.
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PMID:Influence of age on thermotropic kinetics of enzymes involved in mitochondrial energy-metabolism. 21 32

Taking into account the found earlier relation of vitamin E to the ubiquinone functioning and metabolism, the authors studied the enzymic activity of succinate dehydrogenase, NADH-dehydrogenase and cytochrome-c-oxidase--coenzyme Q binding sites of the respiratory chain of the rat liver mitochondria. The experiments were carried out with female rats who received a vitamin-E-deficient diet for 6 months. The enzymic activities and the ubiquinone content in the liver mitochondria of these animals are shown to be considerably lower as compared to the animals received a vitamin E diet; alpha-ocopherol, alpha-tocopheronolactone and ubiquinone 3h after administration manifest a clearly pronounced normalizing effect relative to both the enzymic activity and the ubiquinone content. An assumption is advanced that the effect of alpha-tocopherol and its metabolite is associated with controlling the level of functionally active ubiquinone in the mitochondria. Other mechanisms of the membrane-bound enzymes control by the compounds under study are also discussed in connection with the alpha-tocopherol effect on the mitochondrial membranes.
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PMID:[Activity of certain redox enzymes of rat liver mitochondria at different levels of dietary vitamin E]. 22 6

Different grades of the colloid stabilizer, polyvinyl alcohol, used for protecting unfixed cryostat sections during cytochemical reactions, may have different effects on enzymatic activity. The influence of three grades of polyvinyl alcohol on the activities of "soluble", membrane-bound and membrane-enclosed enzymes has been investigated in unfixed sections; the activities were measured microdensitometrically. The largest molecular weight polyvinyl alcohol (G18/140, mol. wt. about 90 000) did not retain glucose-6-phosphate dehydrogenase activity in sections of rat liver even when used at the maximum convenient concentration (12%); G04/140 and M05/140 (molecular weights of 15 000 and 25 000 respectively) retained this soluble enzyme if used at concentrations of 30 and 20% respectively. At these concentrations, lactate dehydrogenase activity was apparently decreased when G04/140 and M05/140 were used; this diminished activity has been shown to be due to the need to establish optimal concentrations of reactants for each grade of polyvinyl alcohol and for each reaction. When optimal concentrations of reactants were used, the activities of this enzyme in the presence of each grade of polyvinyl alcohol were identical. The presence of any type of polyvinyl alcohol did not influence the activities of mitochondrial succinate dehydrogenase or of the smooth endoplasmic reticulum enzyme, delta5,3beta-hydroxysteroid dehydrogenase. However, the presence of polyvinyl alcohol improved the state of the section.
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PMID:A quantitative study of the effects of different grades of polyvinyl alcohol on the activities of certain enzymes in unfixed tissue sections. 66 85

Highly purified preparations of cytoplasmic and outer membrane were isolated from aerobically grown Rhodospirillum rubrum lysed by sequential treatment with lysozyme, ethylenediaminetetraacetate, and Brij 58. The membranes were resolved and separated from other cellular constitutents by a combination of velocity and isopyknic sedimentation in sucrose density gradients. On the basis of their appearance in electron micrographs and their protein profiles in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, these preparations appear to be quite similar to those obtained from other gram-negative bacteria. The cytoplasmic membrane fraction contained the majority of the total membrane-bound succinic dehydrogenase activity and was 10-fold enriched in b- and c-type cytochrome with respect to the outer membrane. The latter fraction was characterized by a much greater carbohydrate content and the presence of arachidic acid, which is typical of R. rubrum lipopolysaccharide. Their protein fatty acid, and overall chemical compositions suggested that these preparations were freer from cross-contamination than those obtained from R. rubrum with currently available methods.
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PMID:Membranes of Rhodospirillum rubrum: isolation and physicochemical properties of membranes from aerobically grown cells. 82 Jun 89

The distribution of oestrogen-induced peroxidase in the resuspended 8000g pellet of rat uterine homogenates was examined by centrifugation in a sucrose density gradient. Within 10h of treatment with oestradiol, peroxidase activity was found in a region devoid of catalase or urate oxidase (peroxisomal markers) which did not overlap the fractions containing succinate dehydrogenase (mitochondrial marker) or acid phosphatase (lysosomal marker). The induced uterine enzyme was localized in reticular membrane-bound vesicles with isopycnic density of 1.28g/ml from which it could be released by treatment with detergent.
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PMID:Subcellular localization of oestrogen-induced uterine peroxidase. 100 53

Site-directed mutants of Escherichia coli fumarate reductase in which FrdB Cys204, Cys210, and Cys214 were individually replaced by Ser and in which Val207 was replaced by Cys were constructed and overexpressed in a strain of E. coli lacking a wild-type copy of fumarate reductase and succinate dehydrogenase. The consequences of these mutations on bacterial growth, enzymatic activity, and the EPR properties of the constituent iron-sulfur clusters were investigated. The FrdB Cys204Ser, Cys210Ser, and Cys214Ser mutations result in enzymes with negligible activity that have dissociated from the membrane and consequently are incapable of supporting cell growth under conditions requiring a functional fumarate reductase. EPR studies indicate that these effects are associated with loss of both the [3Fe-4S] and [4Fe-4S] clusters, centers 3 and 2, respectively. In contrast, the FrdB Val207Cys mutation results in a functional membrane-bound enzyme that is able to support growth under anaerobic and aerobic conditions. However, EPR studies indicate that the indigenous [3Fe-4S]+,0 cluster (Em = -70 mV), center 3, has been replaced by a much lower potential [4Fe-4S]2+,+ cluster (Em = -350 mV), indicating that the primary sequence of the polypeptide determines the type of clusters assembled. The results of these studies afford new insights into the role of centers 2 and 3 in mediating electron transfer from menaquinol, the residues that ligate these clusters, and the intercluster magnetic interactions in the wild-type enzyme.
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PMID:[3Fe-4S] to [4Fe-4S] cluster conversion in Escherichia coli fumarate reductase by site-directed mutagenesis. 131 45


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