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)

The ability of the oxidized and singly reduced species of several bipyridylium cations to cross the cytoplasmic membrane of Escherichia coli was studied to locate the sites of reaction of the dyes with anaerobic respiratory enzymes. Benzyl Viologen radical crossed the membrane rapidly, whereas the oxidized species did not. The oxidized or radical species of Methyl Viologen, Morfamquat or Diquat did not rapidly cross the membrane. It was also shown that the dithionite anion does not cross the cytoplasmic membrane of E. coli. Diquat radical donates electrons to the nitrate reductase pathway at the periplasmic aspect of the membrane, whereas Benzyl Viologen radical reacted directly with nitrate reductase itself (EC 1.7.99.4) at the cytoplasmic aspect of the membrane. Thus the pathway of electron transfer in the nitrate reductase pathway is transmembranous. Formate hydrogenlyase (EC 1.2.1.2) and an uncharacterized nitrite reductase activity react with bipyridylium dyes at the periplasmic aspect of the membrane. Fumarate reductase (succinate dehydrogenase; EC 1.3.99.1) reacts with bipyridylium radicals, and formate dehydrogenase (cytochrome) (EC 1.2.2.1) with ferricyanide, at the cytoplasmic aspect of the membrane. The differing charge and membrane permeation of oxidized and radical species of bipyridylium dyes greatly complicate their use as potentiometric mediators in suspensions of cells or membrane vesicles.
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PMID:Sites and specificity of the reaction of bipyridylium compounds with anaerobic respiratory enzymes of Escherichia coli. Effects of permeability barriers imposed by the cytoplasmic membrane. 32 10

The molybdenum requirement for growth and conidial formation by Aspergillus flavus, A. terreus, and A. sulphureus was found to be 0.2 ppb, which was one-fifth that of an A. niger isolate. Molybdenum deficiency depressed growth, conidial formation, dry weight, soluble protein, and the specific activities of nitrate reductase, succinic dehydrogenase, and aconitase in all the isolates of Aspergillus studied, but the specific activities of catalase and peroxidase were depressed only in isolates of A. niger, A. terreus, and A. flavus. Also, molybdenum deficiency stimulated the specific activities of acid phosphatase and ribonuclease in the A. flavus isolate, although the specific activities of these enzymes decreased in other isolates. Eighteen hours after the addition of molybdenum (5 ppb) to molybdenum-deficient (0.02 ppb) cultures of A. niger, the specific activities of catalase, peroxidase and succinic dehydrogenase were restored in the absence of cycloheximide, while the specific activity of nitrate reductase was recovered even in the presence of the inhibitor. There was no effect on the specific activities of aconitase and acid phosphatase following the addition of molybdenum to molybdenum-deficient cultures of A. niger.
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PMID:Molybdenum nutrition of isolates of four Aspergillus species. 309 Dec 28

Antibodies were elicited to FAD by using the hapten N-6-(6-aminohexyl)-FAD conjugated to the immunogenic carrier protein bovine serum albumin. Cross-reactivity was determined by Ouchterlony double-diffusion analysis with N-6-(6-aminohexyl)-FAD coupled to rabbit serum albumin. Anti-FAD IgG was partially purified by (NH4)2SO4 precipitation followed by DEAE-cellulose/CM-cellulose and bovine serum albumin-agarose chromatography. The partially purified anti-FAD IgG fraction failed to inhibit the catalytic activities of the flavin-containing enzymes nitrate reductase, xanthine oxidase and succinate dehydrogenase, whereas enzyme activity could be inhibited by addition of antibodies elicited against the native proteins. However, the partially purified anti-FAD IgG fraction could be used as a highly sensitive and specific probe to detect proteins containing only covalently bound flavin, such as succinate dehydrogenase, p-cresol methylhydroxylase and monoamine oxidase, by immuno-blotting techniques. Detection limits were estimated to be of the order of femtomolar concentrations of FAD with increased sensitivity for the 8 alpha-N(3)-histidyl linkage compared with 8 alpha-O-tyrosyl substitution.
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PMID:Anti-flavin antibodies. 310 86

The effect of sugar mill effluent on the activities of peroxidase, amylase, and nitrate reductase of rice (Oryza Sativa L. C.V. Mushoori) seedlings have been investigated. In addition, an attempt was also made to investigate effluent-induced changes in the activities of mitochondrial enzymes, such as succinate dehydrogenase, during germination of rice seedlings. The effects were studied in relation to both concentration of effluent and time of exposure. The activity of all enzymes tested, except succinate dehydrogenase, decreased during effluent treatment. A marked increase in succinate dehydrogenase activity was noticed at various concentrations of effluent treatment. When time-dependent changes in succinate dehydrogenase activity were followed a nearly threefold increase was found with 12 hr of treatment after which a rapid loss was noticed. A correlation was established between the retardation of growth and development of effluent-treated rice seedlings with the activities of some key enzymes regulating growth and development.
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PMID:The effect of sugar mill effluent on enzyme activities of rice seedlings. 316 May 78

Envelope preparations obtained by passing Escherichia coli cells through a French pressure cell were separated by sucrose density gradient centrifugation into two distinct particulate fractions. The fraction with the higher density was enriched in fragments derived from the cell wall, as indicated by the high content of lipopolysaccharide, the low content of cytochromes, and the similar morphology of the fragments and intact cell walls. The less-dense fraction was enriched in vesicles derived from the cytoplasmic membrane, as indicated by the enrichment of cytochromes, the enzymes lactic and succinic dehydrogenase and nitrate reductase, and the morphological similarity of the vesicles to intact cytoplasmic membrane. Both fractions were rich in phospholipid. The protein composition was compared by mixing the cytoplasmic membrane-enriched fraction from a (3)H-labeled culture with the cell wall-enriched fraction from a (14)C-labeled culture and examining the resulting mixture by gel electrophoresis. Thirty-four bands of radioactive protein were resolved; of these, 27 were increased two- to fourfold in the cytoplasmic membrane-enriched fraction, whereas 6 were similarly increased in the cell wall-enriched fraction. One of the proteins which is clearly localized in the cell wall is the protein with a molecular weight of 44,000, which is the major component of the envelope. This protein accounted for 70% of the total protein of the cell wall, and its occurrence in the envelope from spheroplasts suggests that it is a structural protein of the outer membranous component of the cell wall.
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PMID:Protein composition of the cell wall and cytoplasmic membrane of Escherichia coli. 409 97

Chlorate-resistant mutants corresponding to each known genetic locus (chlA, chlB, chlC, chlD, chlE) were isolated from Escherichia coli K-12. All these mutants showed decreased amounts of membrane-bound nitrate reductase, cytochrome b, and formic dehydrogenase, but all had normal succinic dehydrogenase activity. Proteins from the cytoplasmic membranes of these mutants were compared to those of the wild type-on polyacrylamide gels. The addition of nitrate to wild-type anaerobic cultures caused increased formation of three membrane proteins. These same proteins, along with one other, were missing in varying patterns in mutants altered at the different genetic loci. One of the missing proteins was found to be the enzyme nitrate reductase, although this protein was present in some mutants lacking nitrate reductase activity. None of the others has been identified.
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PMID:Alterations in the cytoplasmic membrane proteins of various chlorate-resistant mutants of Escherichia coli. 494 70

The NIT2 nitrogen regulatory protein of Neurospora is a DNA binding protein which contains a single Cys2/Cys2 type finger motif followed immediately by a highly basic region. Several different approaches were employed to identify nucleotides which appear to be in contact with NIT2 in the DNA-protein complex. Methylation interference and missing contact analyses with the promoter DNA fragment of the L-amino acid oxidase gene showed that all three purines in both of two GATA core sequences and the single adenine residue in each of the complementary TATC sequences were in intimate contact with NIT2. Modification or loss of the three purine residues located between the two GATA core sequences also significantly reduced NIT2 binding, whereas alteration of purines which flank the binding element showed only minor effects. Chemical modification of all six thymine bases in the two GATA and TATC complement core sequences also strongly affected NIT2 binding. High affinity NIT2 binding sites appear to contain at least two GATA core sequences, with single GATA sequences acting only as weak binding sites. Mobility shift experiments with the DNA fragment upstream of nit-3, the structural gene for nitrate reductase, revealed two DNA-NIT2 protein complexes. In complex I, which is formed first, NIT2 was bound to a pair of GATA sites located at -180. In complex II, the paired GATA sites at -180 plus a single GATA site at -290 were all occupied by NIT2. A DNA fragment containing only the single -290 GATA element bound NIT2 very weakly. The affinity of this single GATA for NIT2 was ten to twenty times greater when it was situated on the same DNA fragment with the distant paired GATA elements than when alone.
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PMID:Recognition of specific nucleotide bases and cooperative DNA binding by the trans-acting nitrogen regulatory protein NIT2 of Neurospora crassa. 839 61

The mRNA level of the aconitase gene acn of Corynebacterium glutamicum is reduced under iron limitation. Here we show that an AraC-type regulator, termed RipA for "regulator of iron proteins A," is involved in this type of regulation. A C. glutamicum DeltaripA mutant has a 2-fold higher aconitase activity than the wild type under iron limitation, but not under iron excess. Comparison of the mRNA profiles of the DeltaripA mutant and the wild type revealed that the acn mRNA level was increased in the DeltaripA mutant under iron limitation, but not under iron excess, indicating a repressor function of RipA. Besides acn, some other genes showed increased mRNA levels in the DeltaripA mutant under iron starvation (i.e. those encoding succinate dehydrogenase (sdhCAB), nitrate/nitrite transporter and nitrate reductase (narKGHJI), isopropylmalate dehydratase (leuCD), catechol 1,2-dioxygenase (catA), and phosphotransacetylase (pta)). Most of these proteins contain iron. Purified RipA binds to the upstream regions of all operons mentioned above and in addition to that of the catalase gene (katA). From 13 identified binding sites, the RipA consensus binding motif RRGCGN(4)RYGAC was deduced. Expression of ripA itself is repressed under iron excess by DtxR, since purified DtxR binds to a well conserved binding site upstream of ripA. Thus, repression of acn and the other target genes indicated above under iron limitation involves a regulatory cascade of two repressors, DtxR and its target RipA. The modulation of the intracellular iron usage by RipA supplements mechanisms for iron acquisition that are directly regulated by DtxR.
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PMID:The AraC-type regulator RipA represses aconitase and other iron proteins from Corynebacterium under iron limitation and is itself repressed by DtxR. 1617 44

The bc(1) respiratory complex III constitutes a key energy-conserving respiratory electron transporter between complex I (type I NADH dehydrogenase) and II (succinate dehydrogenase) and the final nitrogen oxide reductases (Nir, Nor and Nos) in most denitrifying bacteria. However, we show that the expression of complex III from Thermus thermophilus is repressed under denitrification, and that its role as electron transporter is replaced by an unusual nitrate reductase (Nar) that contains a periplasmic cytochrome c (NarC). Several lines of evidence support this conclusion: (i) nitrite and NO are as effective signals as nitrate for the induction of Nar; (ii) narC mutants are defective in anaerobic growth with nitrite, NO and N2O; (iii) such mutants present decreased NADH oxidation coupled to these electron acceptors; and (iv) complementation assays of the mutants reveal that the membrane-distal heme c of NarC was necessary for anaerobic growth with nitrite, whereas the membrane-proximal heme c was not. Finally, we show evidence to support that Nrc, the main NADH oxidative activity in denitrification, interacts with Nar through their respective membrane subunits. Thus, we propose the existence of a Nrc-Nar respiratory super-complex that is required for the development of the whole denitrification pathway in T. thermophilus.
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PMID:A cytochrome c containing nitrate reductase plays a role in electron transport for denitrification in Thermus thermophilus without involvement of the bc respiratory complex. 1876 83

This study explored the chronic and harmful effects of different doses of the triazole fungicide, tebuconazole, on the growth, and metabolic and enzymatic variations in the filamentous paddy field cyanobacterium, Westiellopsis prolifica Janet. The growth of the cyanobacterium was determined by an estimation of the change in pigment contents. Chlorophyll-a, carotenoids and accessory pigments such as phycocyanin, allophycocyanin and phycoerythrin, were shown to decline over a 16-day period by a factor of 92%, 93%, 83%, 95% and 100%, respectively, with increasing doses of the fungicide. Metabolic and enzymatic activities were also adversely affected. Over the 16 days, a gradual rise in the total phenol content was recorded when Westiellopsis prolifica Janet was treated with 60 ppm of the fungicide, despite the reduction in carbohydrates, proteins and amino acids by 96%, 92% and 90%, respectively. Moreover, the enzymes nitrate reductase (NR), glutamine synthetase (GS) and succinate dehydrogenase (SDH) also registered reductions of 93%, 90% and 98%, respectively. This study indicates that tebuconazole, although an important fungicide used extensively in rice fields, exhibits an inhibitory effect on the growth and metabolic activities of Westiellopsis prolifica Janet and hence possibly on other varieties as well.
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PMID:Chronic toxicity of a triazole fungicide tebuconazole on the growth and metabolic activities of heterocystous, nitrogen-fixing paddy field cyanobacterium, Westiellopsis prolifica Janet. 2066 8


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