Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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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)

1. Mitochondrial and microsomal fractions were prepared from normal rat liver and the Morris 7777 hepatoma and characterized by the use of the marker enzymes, succinate dehydrogenase and rotenone-insensitive NADPH-cytochrome c reductase. 2. The phospholipid content per mg membrane protein of Morris 7777 hepatoma mitochondria was increased by 75% as compared with mitochondria from normal rat liver. Microsomes from this poorly-differentiated tumor were found to have a 45% decrease in the content of phospholipid. These abnormalities were independent of tumor size or age. 3. The percent phospholipid content of the subcellular fractions was determined, and revealed an increase in the percent sphingomyelin in both the microsomal and mitochondrial fractions of the tumor. Decreases in the percent phosphatidylcholine and phosphatidylethanolamine were noted in tumor microsomes as compared with normal liver. Diphosphatidylglycerol was not found in significant quantities in the microsomal fraction of this hepatoma line. 4. The content of the various phospholipid classes per mg protein in the respective mitochondrial and microsomal fractions was determined. Large increases in nearly all the major phospholipid classes were found in tumor mitochondria; tumor microsomes were characterized by an increased content of sphingomyelin but the content of nearly all other phospholipids was significantly decreased. These findings suggest the presence of disturbances in the regulation of phospholipid metabolism in subcellular organelle membranes of the Morris 7777 hepatoma.
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PMID:Abnormal membrane phospholipid content in subcellular fractions from the Morris 7777 hepatoma. 18 53

Fumarate reductase has been purified 100-fold to 95% homogeneity from the cytoplasmic membrane of Escherichia coli, grown anaerobically on a defined medium containing glycerol plus fumarate. Optimal solubilization of total membrane protein and fumarate reductase activity occurred with nonionic detergents having a hydrophobic-lipophilic balance (HLB) number near 13 and we routinely solubilized the enzyme with Triton X-100 (HLB number = 13.5). Membrane enzyme extracts were fractionated by hydrophobic-exchange chromatography on phenyl Sepharose CL-4B to yield purified enzyme. The enzyme whether membrane bound, in Triton extracts, or purified, had an apparent Km near 0.42 mM. Two peptides with molecular weights of 70 000 and 24 000, predent in 1:1 molar ratios, were identified by sodium dodecyl sulfate polyacrylamide slab-gel electrophoresis to coincide with enzyme activity. A minimal native molecular weight of 100 000 was calculated for fumarate reductase by Stephacryl S-200 gel filtration in the presence of sodium cholate. This would indicate that the enzyme is a dimer. The purified enzyme has low, but measurable, succinate dehydrogenase activity.
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PMID:Purification and characterization of membrane-bound fumarate reductase from anaerobically grown Escherichia coli. 38 38

Cells of Rhodopseudomonas capsulata, strain 37b4, leu-, precultivated anaerobically under low light intensity, were exposed to high light intensity (2000 W.m-2). The cells grew with a mass doubling time of 3 h. The synthesis of bacteriochlorophyll (BChl) began after two doublings of cell mass. Reaction center and light-harvesting BChl I (B-875) were the main constituents of the photosynthetic apparatus incorporated into the membrane. The size of the photosynthetic unit (total BChl/reaction center) decreased and light-harvesting BChl I became the dominating BChl species. Concomitant with the appearance of the different spectral forms of BChl the respective proteins were incorporated into the membrane, i.e. the three reaction center polypeptides, the polypeptide associated with light-harvesting BChl I, the two polypeptides associated with BChl II. A polypeptide of an apparent molecular weight of 45 000 was also incorporated. A lowering of the light intensity to 7 W.m-2 resulted in a lag phase of growth for 6 h. Afterwards, the time for doubling of cell mass was 11 h. The concentration of all three BChl complexes (reaction center, light-harvesting BChl I and II complexes)/cell and per membrane protein increased immediately. Also the size of the photosynthetic unit and the amount of intracytoplasmic membranes/cell increased. The activities of photophosphorylation, succinate dehydrogenase, NADH dehydrogenase and NADH oxidation (respiratory chain)/membrane protein are higher in membrane preparations isolated from cells grown at high light intensities than in such preparations from cells grown at low light intensities.
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PMID:Effects of light intensity on membrane differentiation in Rhodopseudomonas capsulata. 48 32

The cell envelope of Neisseria gonorrhoeae, colony type 4, was studied. Outer membrane was isolated by lysozyme and ethylenediaminetetraacetic acid treatment of plasmolyzed cells according to Wolf-Watz et al. (1973). The degree of purity of the membrane preparations was checked by electron microscopy. The membrane fraction obtained had a density of 1.25 g/cm(3), was rich in phospholipase A and lysophospholipase, and contained only 10% of the total membrane activity of succinate dehydrogenase and d-lactate dehydrogenase. The outer membrane protein profile after sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed at least six major proteins. The predominating protein showed a molecular weight of 35,000. The lipopolysaccharide component was characterized by gas chromatography. The carbohydrates found were galactose, glucose, and glucosamine. d-Glycero-l-manno-heptose was present in very low amounts. Lipid A contained lauric acid, stearic acid, and beta-hydroxy-myristic acid. About 20% of the fatty acids in the outer membrane was derived from lipid A. The phospholipids were characterized as phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. There was no evidence for a lipoprotein anchored to the peptidoglycan. The peptidoglycan of N. gonorrhoeae was of the chemotype I. The cell envelope of N. gonorrhoeae was found to be highly permeable to gentian violet. Cell envelopes of one penicillin-resistant and two penicillin-sensitive strains were compared. Only moderate differences in fatty acid composition were found.
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PMID:Cell envelope of Neisseria gonorrhoeae: outer membrane and peptidoglycan composition of penicillin-sensitive and-resistant strains. 80 26

The membrane-bound succinate dehydrogenase (SDH; EC 1.3.99.1) of Bacillus pumilus strain 5 was investigated as succinate:ferricyanide oxidoreductase activity at 27 degrees C. A Km of 8.3 x 10(-3) M was obtained, and the Vmax was 1.8 x 10(-6) mole succinate dehydrogenated min-1 mg-1 membrane protein, at a substrate (succinate) concentration below 40 x 10(-3) M. Above this succinate concentration the Km was 102 x 10(-3) M and the Vmax was 3.7 x 10(-6) mole succinate min-1 mg-1 membrane protein. Para-benzoquinone or 2,4-dinitrophenylhydrazine, in micromolar amounts inhibited the enzyme by serving as an electron sink. Hydroxyl radical (OH.) scavengers, mannitol and benzoate, activated the enzyme, while superoxide dismutase (SOD) had no effect on the enzyme. Thus, the mechanism of electron transfer from succinate to Fe(CN)3-(6) through SDH does not involve superoxide (O2-) as a rate-limiting intermediate.
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PMID:Membrane-bound succinate dehydrogenase of Bacillus pumilus strain 5: effects of modulators of monoelectron transfer. 251 38

A new surfactant, 6-O-(N-heptylcarbamoyl)-methyl-alpha-D-glucopyranoside (HECAMEG, molar mass 335.38 g), was synthesized by a simple and low cost procedure from methyl-alpha-D-glucopyranoside. This surfactant is characterized by a high solubility in water (even at 0 degree C), ultraviolet light transparency in the region useful for protein detection, and a high critical micellar concentration (CMC = 19.5 mM), permitting fast elimination by dialysis. Furthermore, the surfactant is colorimetrically titratable by the anthrone technique and its weak interference in protein titration by the Lowry et al. procedure and the bicinchoninic method is easy to overcome. Two membrane proteins (NADH oxidase and succinate dehydrogenase) and a soluble enzyme (lactoperoxidase) retained full activity in the presence of HECAMEG below or above its CMC. The partial inhibition of beta-lactamase (soluble form) by HECAMEG above the CMC was probably only apparent and due to an interference of the surfactant with the substrate rather than a direct effect on the enzyme. HECAMEG was capable of extracting up to 75% of bacteriorhodopsin from the purple membrane of Halobacterium halobium in a nondenatured form as indicated by the spectral properties of the protein. It also solubilized spiralin from the Spiroplasma melliferum membrane with a great selectivity and efficiency, without detectable loss of antigenic properties. These data show that HECAMEG is a very mild surfactant, useful for membrane protein studies.
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PMID:Synthesis and characterization of 6-O-(N-heptylcarbamoyl)-methyl-alpha-D-glucopyranoside, a new surfactant for membrane studies. 275 88

Bacillus subtilis cytochrome b558 is a transmembrane protein which anchors succinate dehydrogenase (SDH) to the cytoplasmic membrane and is reduced by succinate. The structural gene for this cytochrome was cloned and expressed in Escherichia coli. Random BamHI or BglII fragments of B. subtilis 168 DNA were cloned in the BamHI site of plasmid pHV32. The derived plasmids were used to transform B. subtilis SDH mutants to chloramphenicol resistance by integration of the plasmid via DNA homology. Of some 3,000 transformants tested, 6 were SDH positive and had pHV32 integrated close to the sdh operon. Two plasmids, pKIM2 and pKIM4, with an insert of B. subtilis DNA of 5.7 and 3.4 kilobases, respectively, were generated by transforming E. coli with DNA from the SDH-positive transformants after cleavage with EcoRI or BglII and ligation. In E. coli carrying either of the two plasmids, about 4% of total membrane protein was B. subtilis cytochrome b558. E. coli (pKIM2) also contained antigen which reacted with antibodies specific for the flavoprotein and the iron-sulfur protein subunit of B. subtilis SDH. Enzymatically active, membrane-bound B. subtilis SDH could not be demonstrated in E. coli (pKIM2). The B. subtilis DNA insert in pKIM2 could transform B. subtilis sdhA (cytochrome b558), sdhB (flavoprotein), and sdhC (iron-sulfur protein) mutants to the wild type. The results suggest that pKIM2 carries the whole B. subtilis sdh operon. The data confirm the gene order and the proposed direction of transcription of the B. subtilis sdh operon. Most likely the sdh genes in E. coli(pKIM2) are controlled by their natural promoter.
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PMID:Cloning and expression in Escherichia coli of sdhA, the structural gene for cytochrome b558 of the Bacillus subtilis succinate dehydrogenase complex. 298 85

Lipid composition of plasma membranes from luteal cells was examined to determine whether changes in this organelle occur during regression and maintenance of the corpus luteum in nonpregnant (NP) and pregnant (P) ewes, respectively. Forty ewes were assigned to be killed on Day 13 or 15 of the estrous cycle (D13-NP and D15-NP) or pregnancy (D13-P and D15-P). Purification of luteal plasma membranes on discontinuous sucrose gradients yielded two fractions, designated F1 and F2, that exhibited the greatest enrichment of 5'-nucleotidase activity (five- and fourfold, respectively) over that of the homogenate. These fractions also yielded the lowest contamination by endoplasmic reticulum as represented by nicotinamide adenine dinucleotide phosphate (NADPH) cytochrome C reductase activity and mitochondrial membranes as indicated by succinate dehydrogenase activity. Predominant phospholipids identified in membranes obtained from all groups were phosphatidylcholine (PC, 48.9 +/- 0.6% of total phospholipid), phosphatidylethanolamine (PE, 33.3 +/- 0.4%), sphingomyelin (SPH, 9.7 +/- 0.3%), phosphatidylserine (PS, 3.5 +/- 0.2%), and phosphatidylinositol (PI, 4.0 +/- 0.5%). No changes in microgram phospholipid/mg membrane protein were observed for any luteal phospholipid on D13 and 15 of the estrous cycle or pregnancy. No significant changes in the relative percentages of major fatty acids present in PC (palmitic [16:0], oleic [18:1]), PE (stearic [18:0], 18:1 and arachidonic [20:4]), or PS (18:0, 18:1, docosatetraenoic [22:4]), nor in the ratios of unsaturated (U) to saturated (S) fatty acids in these phospholipids were observed. Significant differences in unsaturated fatty acids of chain length greater than 20 carbons present in minor quantities in PC, PE, and PS were detected between NP and P ewes as well as between days within reproductive stage. The profile of major fatty acids present in PI revealed decreases in 18:0 and 20:4 in D15-NP and increases in 22:4 and docosapentaenoic acid (22:5) in luteal membranes of both D13- and D15-NP ewes relative to the levels of these fatty acids in PI of corresponding groups of pregnant ewes. There was a general trend for 20:4 levels of PC and PI in membranes of D15-NP ewes to be inversely related to those of D15-P ewes. Collectively, these changes were reflected by an increased U:S fatty acid ratio in luteal membrane PI during the estrous cycle. Specific binding of [125I] iodo-human chorionic gonadotropin to luteal plasma membranes from NP and P ewes on D13 and 15 (6/group) revealed similar affinities and concentrations of unoccupied luteinizing hormone (LH) receptors.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Characterization of plasma membrane lipids and luteinizing hormone receptors of ovine corpora lutea during luteolysis and early pregnancy. 340 35

Synthesis of bacterial membranes has been investigated in Bacillus subtilis by examining incorporation of amino acids and glycerol into the protein and lipid of membranes of synchronous cultures. A simple reproducible fractionation scheme divides cellular proteins into three classes (i) truly cytoplasmic, (ii) loosely membrane bound, released by chelating agents, and (iii) tightly membrane bound. These comprise approximately 75, 10, and 15%, respectively, of cellular proteins in this organism. Incorporation of radioactivity into these fractions, using steady-state and pulse labeling has been followed during the cell cycle. Cytoplasmic proteins and the loosely membrane-bound proteins are labeled at an exponential rate throughout the cell cycle. The membrane fraction is labeled discontinuously in the cell cycle, with periods of rapid synthesis over the latter part of the cycle and a period with no net synthesis during the early part of the cycle. Pulse labeling indicates that synthesis of membrane occurs at a linear rate that doubles at a fixed time in each cycle, which coincides with the period of zero net synthesis. Rates of membrane synthesis measured by pulse labeling during the period of rapid membrane synthesis are significantly less than indicated by steady-state labeling. These discrepancies are consistent with the hypothesis that during the cell cycle certain proteins are added to the membrane from the cytoplasm and that during the period of zero net synthesis there is an efflux of proteins from the membrane. Evidence in favor of this has been presented. The activity of succinic dehydrogenase (a representative of class c) varies in a step-wise manner with periods of rapid increase, approximately coincident with bursts of membrane protein synthesis, alternating with periods without any increase in activity. The activities of malate dehydrogenase (class a) and reduced nicotinamide adenine dinucleotide dehydrogenase (class b) increased throughout the cell cycle. Phospholipid synthesis is continuous throughout the cell cycle.
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PMID:Membrane synthesis in synchronous cultures of Bacillus subtilis 168. 412 17

The inner and outer membranes of Pasteurella haemolytica were separated by sucrose density gradient centrifugation after plasmolysis of the cells in 20% sucrose and fragmentation in a French pressure cell. Assays of the two membrane fractions for 2-keto-3-deoxyoctonate, succinate dehydrogenase, and NADH dehydrogenase and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that each of the two membrane fractions was purified fivefold relative to the other. The outer membrane fraction contained two major proteins of molecular weights 30,000 and 42,000 (30K and 42K proteins), and the inner membrane fraction contained five proteins in approximately equal amounts. Intact bacteria as well as membrane fractions were extracted by procedures used by others for vaccine preparation to determine whether the outer membrane proteins were released. Extraction of the isolated membranes with 0.5 M potassium thiocyanate in 0.425 M NaCl with or without EDTA or with M sodium salicylate failed to release more than traces of the outer membrane proteins. Sodium dodecyl sulfate extracted essentially all of the proteins of both membranes, but the products of this procedure were of low solubility and presumably denatured. The inner membrane proteins were extracted with 0.5% Sarkosyl in 0.02 M sodium phosphate buffer (pH 7.5). The 42K outer membrane protein, most of the lipopolysaccharide, and some of the 30K outer membrane protein were extracted with 1% Zwittergent 3-16 in 0.25 M NaCl (pH 8), and the remaining 30K outer membrane protein was extracted with 1% deoxycholate in 0.25% NaCl (pH 8). Extraction of membranes in this sequence yielded partially purified membrane proteins that were soluble in dilute buffers.
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PMID:Identification and extraction of Pasteurella haemolytica membrane proteins. 620 95


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