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 effect of endurance training on skeletal muscle myoglobin concentration in man was investigated. 8 healthy sedentary males (20-31 yrs) trained on cycle ergometers 40 min/day, 4 days a week for 8 weeks. The work consisted of continuous exercise at a work load that during the last 5 weeks corresponded to 75% of the pretraining maximal oxygen uptake (VO2 max). The training program resulted in a 7% increase in VO2 max (p less than 0.01). The activities of the mitochondrial enzymes citrate synthase (CS), succinate dehydrogenase (SDH) and cytochrome c oxidase (Cyt-c-ox) in the quadriceps femoris muscle, as indicators of muscle respiratory capacity, increased by 62-82% (p less than 0.01). The metabolic adaptation of skeletal muscle was further indicated by a 17% increase in the work load corresponding to a blood lactate concentration of 4 mmol/l, as determined by a progressive exercise test (p less than 0.05). There was, however, no change in the myoglobin concentration of the thigh muscle with training (-1%, NS). It is suggested that endurance exercise in man at 75% of the maximal oxygen uptake does not severely tax the functions of myoglobin in skeletal muscle.
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PMID:Dissociation of training effects on skeletal muscle mitochondrial enzymes and myoglobin in man. 630 98

The nucleotide sequence of a 3614 base-pair segment of DNA containing the sdhA gene, encoding the flavoprotein subunit of succinate dehydrogenase of Escherichia coli, and two genes sdhC and sdhD, encoding small hydrophobic subunits, has been determined. Together with the iron-sulphur protein gene (sdhB) these genes form an operon (sdhCDAB) situated between the citrate synthase gene (gltA) and the 2-oxoglutarate dehydrogenase complex genes (sucAB): gltA-sdhCDAB-sucAB. Transcription of the gltA and sdhCDAB gene appears to diverge from a single intergenic region that contains two pairs of potential promoter sequences and two putative CRP (cyclic AMP receptor protein)-binding sites. The sdhA structural gene comprises 1761 base-pairs (587 codons, excluding the initiation codon, AUG) and it encodes a polypeptide of Mr 64268 that is strikingly homologous with the flavoprotein subunit of fumarate reductase (frdA gene product). The FAD-binding region, including the histidine residue at the FAD-attachment site, has been identified by its homology with other flavoproteins and with the flavopeptide of the bovine heart mitochondrial succinate dehydrogenase. Potential active-site cysteine and histidine residues have also been indicated by the comparisons. The sdhC (384 base-pairs) and sdhD (342 base-pairs) structural genes encode two strongly hydrophobic proteins of Mr 14167 and 12792 respectively. These proteins resemble in size and composition, but not sequence, the membrane anchor proteins of fumarate reductase (the frdC and frdD gene products).
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PMID:Nucleotide sequence encoding the flavoprotein and hydrophobic subunits of the succinate dehydrogenase of Escherichia coli. 638 59

The nucleotide sequence of a 961 base-pair segment of DNA containing the sdhB gene, which encodes the iron-sulphur protein subunit of the E. coli succinate dehydrogenase, has been determined. The sdhB structural gene comprises 711 base pairs (237 codons, excluding the translational initiator and terminator). It is separated by a 15 base-pair intergenic region from the preceding flavoprotein gene (sdhA) and is the distal gene of an operon that also includes genes (sdhC and D) encoding two hydrophobic subunits, sdhCDAB. The distal end of the sdh operon is linked to the 2-oxoglutarate dehydrogenase gene (sucA) by a complex region of dyad symmetry that is homologous with several potential intercistronic regulatory elements or transcriptional attenuators. The sdhB structural gene encodes a polypeptide of Mr26637 that is strikingly homologous with the iron-sulphur protein subunit of fumarate reductase (38% identity, increasing to 58% when conservative changes are included). Both subunits contain 11 cysteine residues, 10 being conserved in three clusters resembling those found in ferredoxins. This work completes the sequence of a 9897 base-pair segment of DNA containing seven tricarboxylic acid cycle genes encoding three enzymes or enzyme complexes, citrate synthase (gltA), succinate dehydrogenase (sdh), and the 2-oxoglutarate dehydrogenase complex (suc), that are organized thus: gltA-sdhCDAB-sucAB.
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PMID:Nucleotide sequence encoding the iron-sulphur protein subunit of the succinate dehydrogenase of Escherichia coli. 638 71

NADH:ubiquinone reductase (complex I) of the mitochondrial inner membrane respiratory chain binds a number of mitochondrial matrix NAD-linked dehydrogenases. These include pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, mitochondrial malate dehydrogenase, and beta-hydroxyacyl-CoA dehydrogenase. No binding was detected between complex I and cytosolic malate dehydrogenase, glutamate dehydrogenase, NAD-isocitrate dehydrogenase, lipoamide dehydrogenase, citrate synthase, or fumarase. The dehydrogenases that bound to complex I did not bind to a preparation of complex II and III, nor did they bind to liposomes. The binding of pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, and mitochondrial malate dehydrogenase to complex I is a saturable process. Based upon the amount of binding observed in these in vitro studies, there is enough inner membrane present in the mitochondria to bind the dehydrogenases in the matrix space. The possible metabolic significance of these interactions is discussed.
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PMID:Complex I binds several mitochondrial NAD-coupled dehydrogenases. 643 16

Rats were given a daily injection of L-epinephrine, 100 micrograms/100 g body wt, for 6 wk. The hearts of the epinephrine-treated animals were heavier (11.5%), and blood glucose and plasma insulin concentrations were lower than those of control rats. Acute responses to epinephrine were compared in the two groups. An increase in blood glucose and decreases in plasma insulin, liver glycogen, and muscle glycogen occurred in both groups. The magnitude of these responses were similar in the two groups except for the decrease in muscle glycogen, which was smaller in the chronic epinephrine-treatment group. There were no changes in respiratory capacity, citrate synthase or succinate dehydrogenase activities, or in cytochrome c concentration in skeletal muscle in response to 6 wk of epinephrine treatment. These results are compatible with the suggestion that catecholamines may play a role in some of the metabolic and cardiac adaptations to exercise training. However, they argue strongly against the hypothesis that catecholamines are responsible for inducing the increase in muscle mitochondria that occurs in response to exercise training.
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PMID:Adaptive responses of rats to prolonged treatment with epinephrine. 645 52

Lizard skeletal muscle fiber types were investigated in the iliofibularis (IF) muscle of the desert iguana (Dipsosaurus dorsalis). Three fiber types were identified based on histochemical staining for myosin ATPase (mATPase), succinic dehydrogenase (SDH), and alphaglycerophosphate dehydrogenase (alphaGPDH) activity. The pale region of the IF contains exclusively fast-twitch-glycolytic (FG) fibers, which stain dark for mATPase and alphaGPDH, light SDH. The red region of the IF contains fast-twitch-oxidative-glycolytic (FOG) fibers, which stain dark for all three enzymes, and tonic fibers, which stain light for mATPase, dark for SDH, and moderate for alphaGPDH. Enzymatic activities of myofibrillar ATPase, citrate synthase, and alphaGPDH confirm these histochemical interpretations. Lizard FG and FOG fibers possess twitch contraction times and resistance to fatigue comparable to analogous fibers in mammals, but are one-half as oxidative and several times as glycolytic as analogous fibers in rats. Lizard tonic fibers demonstrate the acetylcholine sensitivity common to other vertebrate tonic fibers.
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PMID:Histochemical, enzymatic, and contractile properties of skeletal muscle fibers in the lizard Dipsosaurus dorsalis. 645 26

Skeletal limb muscles of the dog could generally be differentiated into three fibre types according to myosin adenosine triphosphatase (ATPase) (pH 9.4) and succinic dehydrogenase activities. However, because this was not always possible, for comparative purposes only, division into low myosin ATPase (slow twitch) type I and high myosin ATPase (fast twitch) type II fibres was used. The percentage of these fibre types in m deltoideus, m triceps brachii caput longum, m vastus lateralis, m gluteus medius, m biceps femoris and m semitendinosus was examined in the greyhound, crossbred and foxhound. In all muscles the greyhound had a significantly higher percentage of fibres with high myosin ATPase activity at pH 9.4 than the other breeds, with almost 100 per cent in most muscles examined. The activities of nine enzymes and glycogen concentration were determined in m gluteus medius and m semitendinosus of the greyhound and crossbred. Significantly higher levels of creatine kinase, aldolase, alanine aminotransferase and citrate synthase and significantly lower activities of 3-hydroxyacyl coenzyme A dehydrogenase and hexokinase were found in both muscles of the greyhound. The implications of these findings are discussed.
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PMID:Skeletal muscle fibre composition in the dog and its relationship to athletic ability. 645 29

The effects of physical training on skeletal muscle morphology and enzyme activities were compared in 10 male, type I diabetic subjects and 10 healthy, male, control subjects. The training program consisted of running for 45 min, three times per week for 8 wk. Muscle biopsies were obtained before and after the training period from the lateral portion of the gastrocnemius muscle. Pretraining maximal oxygen uptake was similar in the two groups (diabetic subjects 42 +/- 1 versus control subjects 43 +/- 2 ml X kg-1 X min-1), and the training resulted in an identical increase (+ 13%, P less than 0.01). Muscle capillarization (number of capillaries per muscle fiber) increased on the average in the control group (+ 14 +/- 4%, P less than 0.01), but was unchanged in the diabetic group (0 +/- 4%). Capillary density, expressed as number of capillaries per unit muscle cross sectional area, also increased on the average in controls (8 +/- 4%, P less than 0.05) but failed to do so in the diabetic patients (-8 +/- 6%, NS). The activities of the mitochondrial enzymes citrate synthase (+ 26-27%, P less than 0.01-0.05) and succinate dehydrogenase (+ 24-25%, P less than 0.05) increased significantly and similarly in the two groups, whereas training did not result in significant changes in the activities of the glycolytic enzymes 6-phosphofructokinase and glyceraldehyde-phosphate dehydrogenase. Glycemic control in the diabetic group did not improve with the training, as evaluated from hemoglobin A1 and home-monitored blood glucose.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Influence of physical training on formation of muscle capillaries in type I diabetes. 646 66

Considerable variations were found in the in vitro effect of alloxan on mouse liver enzymes associated with the citric acid cycle. The following approximative alloxan concentrations induced 50% inhibition of enzyme activity: 10(-6)M for aconitase, 10(-4)M for NAD-linked isocitrate dehydrogenase, glutamate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinyl-CoA synthetase and fumarase, and 10(-3)M for citrate synthase and NADP-linked isocitrate dehydrogenase. Pyruvate dehydrogenase, succinate dehydrogenase and malate dehydrogenase were not inhibited by 10(-3)M alloxan. The inhibition of aconitase was competitive both when using mouse liver and purified porcine heart enzyme. The Ki values for the purified enzyme in the presence of 5 microM alloxan were 0.22 microM with citrate, 4.0 microM with cis-aconitate and 0.62 microM with isocitrate as substrate. The high sensitivity of aconitase for inhibition by alloxan probably plays a prominent role for the toxic effects of alloxan.
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PMID:Inhibition by alloxan of mitochondrial aconitase and other enzymes associated with the citric acid cycle. 651 May 22

Rat kidney homogenates metabolize N6-trimethyl-lysine to N-trimethylammoniobutyrate, but not to carnitine. The first step in this conversion is the hydroxylation of trimethyl-lysine to form 3-hydroxy-N6-trimethyl-lysine. An assay system was developed in which hydroxylation of trimethyl-lysine is linear with respect to both time and homogenate protein concentration. The rate is 5 nmol of 3-hydroxy-N6-trimethyl-lysine formed/min per mg of homogenate protein. The cofactors required are ascorbate, alpha-oxoglutarate, FeSO4, and O2. Catalase and dithiothreitol give a 20% stimulation. Ca2+ produces a 2-fold increase in specific activity and cannot be replaced by Mg2+, Mn2+ or Zn2+. These last three bivalent cations lead to a decreased activity. Subcellular distribution studies demonstrate that trimethyl-lysine hydroxylase activity parallels the distribution profile of succinate dehydrogenase and citrate synthase. Thus trimethyl-lysine hydroxylase has a mitochondrial localization. Distribution of trimethyl-lysine hydroxylase activity between cortex and medulla of kidney if 67 and 33% respectively, similar to mitochondrial distribution.
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PMID:Carnitine biosynthesis. Hydroxylation of N6-trimethyl-lysine to 3-hydroxy-N6-trimethyl-lysine. 677 70


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