Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anterograde or retrograde perfusion of rat liver with digitonin selectively permeabilizes the periportal or the perivenous zone of the hepatic lobule. Digitonin perfusion is used to analyze the effluents released by permeabilized hepatocytes or, combined with collagenase perfusion, to obtain cell suspensions enriched in either periportal or perivenous hepatocytes. Despite the wide use of digitonin to study lobular heterogeneity, its affects on rat hepatocytes are not well documented. We therefore analyzed the effects of digitonin perfusion on the intracellular content of rat hepatocytes by combining electron microscopy, histoenzymology, immunohistochemistry, and in situ hybridization. At the concentration currently used for the study of lobular heterogeneity, digitonin perfusion induced a marked cytosolic clarification of permeabilized hepatocytes, while most organelles except mitochondria were well preserved. In the digitonin-altered zones, there was no histochemical detection of non-membrane-bound enzymes (lactate dehydrogenase, glutamate dehydrogenase), whereas membrane-bound enzymes (succinate dehydrogenase, beta-hydroxybutyrate dehydrogenase, NADPH dehydrogenase, glucose-6-phosphatase) were still detected. Immunohistochemistry and in situ hybridization revealed significant amounts of several plasma proteins (albumin, alpha 2-macroglobulin, alpha 1-inhibitor 3, alpha 1-acid glycoprotein) and their respective mRNAs in digitonin-permeabilized hepatocytes. The demonstration that digitonin-permeabilized hepatocytes retain many intracellular constituents shows that biochemical analysis of cellular effluents released from digitonin-permeabilized hepatocytes must be interpreted with caution and that the apparent characteristics of cell suspensions obtained by the digitonin-collagenase technique might be significantly altered by contamination with permeabilized hepatocytes from the opposite zone.
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PMID:Effects of digitonin on the intracellular content of rat hepatocytes: implications for its use in the study of intralobular heterogeneity. 815 38

Succinic dehydrogenase and cytochrome oxidase have been assayed in permanent cell lines (HEP 1, HEP 2, and HLM), in short-term cultures of chick embryo heart cells, and in various tissues. Their activities in different cells are compared by relating them to deoxyribonucleic acid. They are very low in HEP 1, HEP 2, and HLM cells by comparison with the activities in any normal tissues examined. All the succinic dehydrogenase was shown to be located in the mitochondria of the permanent cell lines by staining with tetrazolium derivatives. Both enzymes were more active in tissues of 19-day chick embryos than in those of 11- or 14-day embryos. The increasing activities found during normal development were quickly curtailed or reversed when heart cells were grown as monolayer cultures. Digitonin-treated mitochondria produced preparations with much higher activities of cytochrome oxidase than untreated samples. Activities measured in this way were again very much lower in HEP 1, HEP 2, and HLM cells than in the normal tissues. From the derived ratio of cytochrome oxidase:succinic dehydrogenase, it was apparent that cytochrome oxidase is diminished to a greater extent than succinic dehydrogenase in both permanent cell lines and short-term cultures, by comparison with the corresponding activities in embryonic and adult tissues. The features common to the metabolism of proliferating cells in vitro and malignant cells are discussed.
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PMID:Succinic dehydrogenase and cytochrome oxidase activities in cell cultures. 1441 95

Mobile light-harvesting complex II (LHCII) is implicated in the regulation of excitation energy distribution between Photosystem I (PSI) and Photosystem II (PSII) during state transitions. To investigate how LHCII interacts with PSI during state transitions, PSI was isolated from Arabidopsis thaliana plants treated with PSII or PSI light. The PSI preparations were made using digitonin. Chemical cross-linking using dithio-bis(succinimidylpropionate) followed by diagonal electrophoresis and immunoblotting showed that the docking site of LHCII (Lhcb1) on PSI is comprised of the PSI-H, -L, and -I subunits. This was confirmed by the lack of energy transfer from LHCII to PSI in the digitonin-PSI isolated from plants lacking PSI-H and -L. Digitonin-PSI was purified further to obtain an LHCII.PSI complex, and two to three times more LHCII was associated with PSI in the wild type in State 2 than in State 1. Lhcb1 was also associated with PSI from plants lacking PSI-K, but PSI from PSI-H, -L, or -O mutants contained only about 30% of Lhcb1 compared with the wild type. Surprisingly, a significant fraction of the LHCII bound to PSI in State 2 was not phosphorylated. Cross-linking prior to sucrose gradient purification resulted in copurification of phosphorylated LHCII in the wild type, but not with PSI from the PSI-H, -L, and -O mutants. The data suggest that migration of LHCII during state transitions cannot be explained sufficiently by different affinity of phosphorylated and unphosphorylated LHCII for PSI but is likely to involve structural changes in thylakoid organization.
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PMID:Light-harvesting complex II binds to several small subunits of photosystem I. 1461 24

Digitonin solubilizes mitochondrial membrane, breaks the integrity of the respiratory chain and releases two mobile redox-active components: coenzyme Q (CoQ) and cytochrome c (cyt c). In the present study we report the inhibition of glycerol-3-phosphate- and succinate-dependent oxygen consumption rates by digitonin treatment. Our results show that the inhibition of oxygen consumption rates is recovered by the addition of exogenous synthetic analog of CoQ idebenone (hydroxydecyl-ubiquinone; IDB) and cyt c. Glycerol-3-phosphate oxidation rate is recovered to 148 % of control values, whereas succinate-dependent oxidation rate only to 68 %. We find a similar effect on the activities of glycerol-3-phosphate and succinate cytochrome c oxidoreductase. Our results also indicate that succinate-dependent oxidation is less sensitive to digitonin treatment and less activated by IDB in comparison with glycerol-3-phosphate-dependent oxidation. These findings might indicate the different mechanism of the electron transfer from two flavoprotein-dependent dehydrogenases (glycerol-3-phosphate dehydrogenase and succinate dehydrogenase) localized on the outer and inner face of the inner mitochondrial membrane, respectively.
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PMID:Idebenone-induced recovery of glycerol-3-phosphate and succinate oxidation inhibited by digitonin. 2248 Apr 20