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)

Five goat latissimus dorsi muscles (LDM) were submitted to a progressive chronic electrostimulation program to reach an integrated understanding of the fast-to-slow transformation process in large mammals. LDM were regularly sampled and followed during a period of 8 months. Each sample was simultaneously assessed for histoenzymological study, myosin and LDH isoforms and bioenergetic capacities [NADH dehydrogenase cytochrome c oxidoreductase (NADH Cyt c OR), succinate dehydrogenase cytochrome c oxidoreductase (Succ Cyt c OR), cytochrome c oxidase (Cyt c Ox) and LDH]. Such muscles were also tested with and without completion of II to I transformation for their mechanical properties in isometric and isotonic strain gauge testing. The conversion of fast-to-slow myosin monitored by heavy chain (HC I) and light chain slow component (LC2s) began a few days after stimulation and was almost 100% after 100 days. The H-LDH isoforms evolved similarly but did not reach 100% conversion after 200 days. The activity of respiratory chain oxidases increased within 36 h but to a variable extent and peaked after 32 days, corresponding to a 75% transformation of myosin compared to initial levels. NADH Cyt c OR, Succ Cyt c OR, and Cyt c Ox, respectively increased 10-, 5- and 5-fold. These activities then significantly decreased before the completion of the myofibrillar transformation and reached a plateau with stable activities that remained 2- to 3-fold higher than the unstimulated LDM. LDH activity sharply decreased until day 62 (5-fold) and then plateaued. Functionally, muscle showed a reduced speed of contraction and moderate reduction in power output but had become fatigue-resistant. This study documents the transformation process in large mammals and suggests the dynamic relation between workload, aerobic-anaerobic metabolism and the contractile myofibrillar system.
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PMID:Type II to type I transformation of chronically stimulated goat latissimus dorsi muscle: a histoenzymological, biochemical, bioenergetic, and functional study. 883 65

Defects of the respiratory chain are a typical feature of mitochondrial diseases and occur also during normal aging where they have been described in postmitotic tissues. The present study addresses the question of defect expression in the normal and cirrhotic liver. Randomly distributed defects of complex III (ubiquinone-cytochrome-c-oxidoreductase) and of complex IV (cytochrome-c-oxidase) of the respiratory chain have been detected with age-related increasing frequency both in normal and cirrhotic livers. No defects were present for complex II (succinate-dehydrogenase) and complex V (adenosine triphosphate-synthase) and in liver cell carcinomas. Sixty-one of 107 normal livers (57%) showed defects of the respiratory chain. The defects occurred in advanced age (over 50 years) in 87%. In contrast 50 of 64 cirrhotic livers (78%) had defects and approximately 60% occurred after age 50. The defects were caused by a loss of enzyme protein involving both nuclearly and mitochondrially coded subunits. Ninety-four percent of the defects (n = 275) involved complex IV selectively. In 4% selective defects of complex III were found and combined defects of both complexes occurred in only 2%. In situ hybridization and polymerase chain reaction (PCR) studies for the detection of the common deletion (4.977 bp) and of various point mutations of mitochondrial DNA (mtDNA) revealed no consistent molecular genetic abnormalities in microdissected respiratory chain defective liver cell areas. Single point mutations at nt 3243 and/or 5692 were found only in 7 of 18 microdissected probes from 6 patients. The results show that defects of the respiratory chain occur already in normal livers most probably during cell aging and at a higher rate in cirrhosis. The random defect pattern favors a stochastic process, e.g., free radical damage. However, the role of mutations of mtDNA remains to be established.
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PMID:Defects of the respiratory chain in the normal human liver and in cirrhosis during aging. 930 2

Complex II (succinate-ubiquinone oxidoreductase) is an important enzyme complex in both the tricarboxylic acid cycle and the aerobic respiratory chains of mitochondria in eukaryotic cells and prokaryotic organisms. In this study, the amino acid sequences of the large (cybL) and small (cybS) subunits of cytochrome b in human liver complex II were deduced from cDNAs isolated by homology probing with mixed primers for the polymerase chain reaction. The mature cybL and cybS contain 140 and 103 amino acids, respectively, and show little similarity to the amino acid sequences of the subunits from other species in contrast to the highly conserved features of the flavoprotein (Fp) subunit and iron-sulfur protein (Ip) subunit. From hydrophobicity analysis, both cybL and cybS appear to have three transmembrane segments, indicating their role as membrane-anchors for the enzyme complex. Histidine residues, which are possible heme axial ligands in cytochrome b of complex II, were found in the second transmembrane segment of each subunit. The genes for cybL (SDHC) and cybS (SDHD) were mapped to chromosome 1q21 and 11q23, respectively by fluorescent in situ hybridization (FISH).
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PMID:Cytochrome b in human complex II (succinate-ubiquinone oxidoreductase): cDNA cloning of the components in liver mitochondria and chromosome assignment of the genes for the large (SDHC) and small (SDHD) subunits to 1q21 and 11q23. 953 30

Our previous studies in iron-loaded rat heart cells showed that in vitro iron loading results in peroxidative injury, manifested in a marked decrease in rate and amplitude of heart cell contractility and rhythmicity, which is correctable by treatment with deferoxamine (DF). In the present studies we explored the role of mitochondrial damage in myocardial iron toxicity. Iron loading by 24-hour incubation with 0.36 mmol/L ferric ammonium citrate resulted in a decrease in the activity of nicotinamide adenine dinucleotide (NADH)-cytochrome c oxidoreductase (complex I+III) to 35.3%+/-11.2% of the value in untreated controls; of succinate-cytochrome c oxidoreductase (complex II+III) to 57.4%+/-3.1%; and of succinate dehydrogenase to 63.5%+/-12.6% (p < 0.001 in all cases). The decrease in activity of other mitochondrial enzymes, including NADH-ferricyanide reductase, succinate ubiquinone oxidoreductase (complex II), cytochrome c oxidase (complex IV), and ubiquinol cytochrome c oxidoreductase (complex III), was less impressive and ranged from 71.5%+/-15.8% to 91.5%+/-14.6% of controls. That the observed loss of respiratory enzyme activity was a specific effect of iron toxicity was clearly demonstrated by the complete restoration of enzyme activities by in vitro iron chelation therapy. Sequential treatment with iron and doxorubicin caused a loss of complex I+III and complex II+III activity that was greater than that seen with either agent alone but was only partially correctable by DF treatment. Alterations in cellular adenosine triphosphate measurements paralleled very closely the changes observed in respiratory complex activity. These findings demonstrate for the first time the impairment of cardiac mitochondrial respiratory enzyme activity caused by iron loading at conditions formerly shown to produce severe abnormalities in contractility and rhythmicity.
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PMID:Mitochondrial respiratory enzymes are a major target of iron toxicity in rat heart cells. 960 12

We have studied the effects of singlet oxygen produced by photodynamic action on respiration in nonphosphorylating mitochondria (state 4). Isolated rat liver mitochondria were incubated with 3 microM hematoporphyrin and irradiated at 365 nm with a fluence rate of 25 W/m2. After short durations of irradiation, state 4 respiration with beta-hydroxybutyrate as substrate increases while respiration with succinate is negligibly affected. When mitochondria have been uncoupled with carbonylcyanide-p-trifluoromethoxyphenyl hydrazone before irradiation, no change occurs in beta-hydroxybutyrate-driven respiration, while succinate-driven respiration strongly decreases. Stimulation of state 4 NADH respiration cannot be explained by slippage of the NADH ubiquinone oxidoreductase because the stoichiometry of the redox pump was found insensitive to photodynamic action. In the light of the metabolite theory for linear enzymatic chains applied to state 4 respiration (Brand et al., Biochem. J. 255, 535-539, 1988), these results suggest that stimulation of NADH respiration is simply due to an increase of membrane leaks which occurs after irradiation. In the case of succinate-driven respiration, a strong inhibition of succinate dehydrogenase activity has been demonstrated after irradiation. It can be suggested that this inhibition introduces a negative control coefficient over state 4 respiration, counterbalancing the effects due to leakage.
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PMID:Effects of photodynamic action on respiration in nonphosphorylating mitochondria. 978 37

The complete nucleotide sequence of the mitochondrial genome of a very primitive unicellular red alga, Cyanidioschyzon merolae , has been determined. The mitochondrial genome of C.merolae contains 34 genes for proteins including unidentified open reading frames (ORFs) (three subunits of cytochrome c oxidase, apocytochrome b protein, three subunits of F1F0-ATPase, seven subunits of NADH ubiquinone oxidoreductase, three subunits of succinate dehydrogenase, four proteins implicated in c-type cytochrome biogenesis, 11 ribosomal subunits and two unidentified open reading frames), three genes for rRNAs and 25 genes for tRNAs. The G+C content of this mitochondrial genome is 27.2%. The genes are encoded on both strands. The genome size is comparatively small for a plant mitochondrial genome (32 211 bp). The mitochondrial genome resembles those of plants in its gene content because it contains several ribosomal protein genes and ORFs shared by other plant mitochondrial genomes. In contrast, it resembles those of animals in the genome organization, because it has very short intergenic regions and no introns. The gene set in this mitochondrial genome is a subset of that of Reclinomonas americana , an amoeboid protozoan. The results suggest that plant mitochondria originate from the same ancestor as other mitochondria and that most genes were lost from the mitochondrial genome at a fairly early stage of the evolution of the plants.
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PMID:Structure and organization of the mitochondrial genome of the unicellular red alga Cyanidioschyzon merolae deduced from the complete nucleotide sequence. 980 18

The functional ability of a muscle is closely related to the activities of the mitochondria, which are energy-producing organelles in muscle cells. The development of the mammalian masticatory muscle progresses dramatically when feeding behavior changes from suckling to mastication, but it is unclear how the energy-producing systems of the mitochondria change. In this paper, the development of rat masticatory muscle mitochondria was investigated in terms of enzyme activities of the mitochondrial respiratory chain and the structural and numerical development of mitochondria, especially regarding the change in feeding behavior from suckling to mastication. Using isolated mitochondria from the masticatory muscle, we measured succinate dehydrogenase, NADH dehydrogenase, succinate-O2 oxidoreductase, and NADH-O2 oxidoreductase. These were found to be increased in the 15-day postnatal rat compared with the 0- to 10-day postnatal rat. The structural development of mitochondria was gradual in the 0- to 15-day postnatal rat. However, a notable increase was found in the cross-sectional area of mitochondria between 10 and 15 days postnatally. The number of mitochondria per muscle fiber was apparently constant during the same period. We demonstrated that the change in feeding behavior was well-correlated with an increase in mitochondrial enzyme activity, also supported by the early structural development of mitochondria.
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PMID:Developmental changes in enzyme activities and in structural features of rat masticatory muscle mitochondria. 982 32

We report the cloning of two variant genes encoding the CII-3 subunit of succinate-ubiquinone oxidoreductase complex II. One gene is located within intron 10 of the human sulfonylurea receptor gene. The 3' boundary of this gene ends in a polymorphic dinucleotide repeat. The second gene CII-3b is expressed at a low level and contains a 102-bp internal deletion compared to CII-3 cDNA. These genes should prove valuable in the characterization of Complex II disorders.
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PMID:A human succinate-ubiquinone oxidoreductase CII-3 subunit gene ending in a polymorphic dinucleotide repeat is located within the sulfonylurea receptor (SUR) gene. 985 82

The mechanisms that lead to mitochondrial damage under oxidative stress conditions were examined in synaptosomes treated with ascorbate/iron. A loss of membrane integrity, evaluated by electron microscopy and by LDH leakage, was observed in peroxidized synaptosomes and it was prevented by pre-incubation with vitamin E (150 microM) and idebenone (50 microM). ATP levels decreased, in synaptosomes exposed to ascorbate/iron, as compared to controls. NADH-ubiquinone oxidoreductase (Cx I) and cytochrome c oxidase (Cx IV) activities were unchanged after ascorbate/iron treatment, whereas succinate-ubiquinone oxidoreductase (Cx II), ubiquinol cytochrome c reductase (Cx III) and ATP-synthase (Cx V) activities were reduced by 55%, 40%, and 55%, respectively. The decrease of complex II and ATP-synthase activities was prevented by reduced glutathione (GSH), whereas the other antioxidants tested (vitamin E and idebenone) were ineffective. However, vitamin E, idebenone and GSH prevented the reduction of complex III activity observed in synaptosomes treated with ascorbate/iron. GSH protective effect suggests that the oxidation of protein SH-groups is involved in the inhibition of complexes II, III and V activity, whereas vitamin E and idebenone protection suggests that membrane lipid peroxidation is also involved in the reduction of complex III activity. These results may indicate that the inhibition of the mitochondrial respiratory chain enzymatic complexes, that are differentially affected by oxidative stress, can be recovered by specific antioxidants.
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PMID:Mitochondrial function is differentially affected upon oxidative stress. 989 Jun 35

The components involved in the respiratory system of the euryarcheon Halobacterium salinarum were investigated by spectroscopic and polarographic techniques. Previous results about the cytochrome composition could be verified. However, under low oxygen tension, the expression of a d-type cytochrome was detected. Membranes exerted an NADH- and succinatecytochrome-c oxidoreductase as well as an NADH and succinate oxidase activity. These activities could be blocked by the following inhibitors: 7-jodocarboxylic acid, giving evidence for the presence of a type II NADH dehydrogenase, antimycin A, and myxothiazol, indicating the presence of a complex III analog, and the typical succinate dehydrogenase (SDH) and terminal oxidase inhibitors. Complex I inhibitors like rotenone and annonine were inactive, clearly excluding the presence of a coupled NADH dehydrogenase. In addition, no [Fe-S] resonances in the region of the NADH dehydrogenase (NDH) clusters could be observed after NADH addition. One of the terminal oxidases could be shown to act as a cytochrome-c oxidase with a Km value of 37 microM and an activation energy of 23.7 kJ/mol. The relative molecular mass of the endogenous c-type cytochrome could be determined as 14.1 kD. The complex III analog could be enriched after detergent extraction with Triton X-100 and hydroxylapatite (HTP) chromatography. The partially purified complex contained a Rieske iron-sulfur cluster, b- and c-type cytochromes, and was catalytically active in the decylubiquinone-cytochrome-c oxidoreductase assay.
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PMID:Studies of the electron transport chain of the euryarcheon Halobacterium salinarum: indications for a type II NADH dehydrogenase and a complex III analog. 993 47


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