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

---

Query: EC:1.3.5.1 (succinate dehydrogenase)
8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Functional properties of the ATPase complex are investigated in megamitochondria isolated from livers of weanling mice fed a diet containing 2% chloramphenicol, as an inhibitor of mitochondrial protein synthesis. 2. Whereas the specific activity of ATPase remains unchanged in chloramphenicol-induced megamitochondria, about 40% of the enyzme activity is resistant to inhibition by oligomycin, triethyltin or venturicidin. It is concluded that the ATPase complex lacks one or more components whose synthesis or accumulation is dependent on mitochondrial translation. The inhibitor-resistant ATPase portion appears tightly bound to the mitochondrial membrane. 3. Respiratory chain phosphorylation is tightly coupled in isolated megamitochondria. ATP synthesis and ATP-Pi exchange are diminished by 40%, as compared to control mitochondria, but both processes are sensitive to oligomycin, triethyltin or venturicidin. 4. The decrease in ATP synthesis and ATP-Pi exchange in megamitochondria correlates quite well with the emergence of inhibitor-resistant ATPase. 5. The following electron transport activities in the megmitochondria are reduced: NADH-cytochrome c reductase, by 60%, cytochrome oxidase, by 80%; the amount of antimycin required to gain complete inhibition of the bc1-segment is diminished by more than 50%. On the other hand succinate dehydrogenase activity is increased by 50%. 6. Chloramphenicol-induced megamitochondria appear to be a useful system for studying the role of mitochondrial translation in the assembly of mammalian mitochondria.
...
PMID:ATPase complex and oxidative phosphorylation in chloramphenicol-induced megamitochondria from mouse liver. 17 30

A study was done to determine whether the Ca2+-activated muscle protease (CAF) that removes Z disks from myofibrils in the presence of Ca2+ is located in a sedimentable subcellular organelle. Porcine skeletal muscle cells were diced finely with a scalpel and were suspended in 0.25 M sucrose, 4 mM EDTA with a VIRTIS homogenizer. Filtration of the suspended muscle through four layers of cheesecloth removed most of the myofibrils and stromal protein. Nuclear (1,000 gavg for 15 min), mitochondrial-microsomal (50,000 gavg for 60 min), and supernatant fractions were assayed for succinic dehydrogenase, acid ribonuclease, cathepsin D, and CAF activities. Approximately 96% of total succinic dehydrogenase activity, 81% of cathepsin D activity, and 45% of acid ribonuclease activity, but only 14% of total CAF activity, were found in the nuclear and mitochondrial-microsomal fractions. Cathepsin D activity in the nuclear and mitochondrial-microsomal fractions was decreased if assays were done without prior treatment to rupture membranous structures; hence, our cell rupture and homogenization procedures preserved some intact lysosomal organelles. The results indicate that the small amount of CAF activity in the nuclear and mitochondrial-microsomal fractions was due to contamination by supernate and that CAF is not located in a membrane-bounded subcellular particle. Because CAF is active at the intracellular pH and temperature of living skeletal muscle cells and is in direct contact with the cytoplasm of muscle cells, its activity must be regulated by intracellular cellular Ca2+ concentration to prevent continuous and indiscriminate degradation of myofibrils.
...
PMID:A Ca2+-activated protease possibly involved in myofibrillar protein turnover. Subcellular localization of the protease in porcine skeletal muscle. 94 76

Rat brown adipocytes were incubated for 24 h with or without norepinephrine (NE) in Dulbecco's modified Eagle's medium with albumin, calf serum, and antibiotics. Brown fat cells were viable as defined by unchanged cell morphology, ATP content, or basal and NE-stimulated respiration. However, a 24-h exposure to NE led to a decline in NE-stimulated respiration that was not due to loss of thermogenic capacity. Brown fat cells incubated with or without NE had similar protein, succinate dehydrogenase, and uncoupling protein (UCP) content. These results differ from those observed after food deprivation in rats where loss of mitochondrial proteins occurs within 24 h, suggesting that reduced exposure to NE is not the only factor responsible for brown fat atrophy. NE increased [35S]methionine incorporation into cellular proteins, mitochondrial proteins, and UCP. The effect of NE on cell protein synthesis was inhibited by propranolol but not by prazosin. It was also inhibited 95% by cycloheximide but only partially (50%) by actinomycin D in contrast to NE stimulation of UCP labeling, which required RNA transcription. Chloramphenicol-sensitive protein synthesis was stimulated by NE. These results indicate a trophic action of NE in brown adipocytes exerted both at the level of RNA transcription and translation.
...
PMID:Characterization of norepinephrine-stimulated protein synthesis in rat brown adipocytes. 144 15

Thyroidectomy and castration in Calotes versicolor significantly decreased the activities of hepatic mitochondrial cytochrome oxidase, alpha-glycerophosphate dehydrogenase (alpha-GPDH), and succinate dehydrogenase (SDH) when compared to sham-operated controls. Administration of thyroid hormones in thyroidectomized lizards and testosterone in castrated specimens stimulated the activities of all three enzymes studied. Chloramphenicol, when injected with thyroxine prevented the hormone-stimulated activities of cytochrome oxidase and SDH, while actinomycin D and chloramphenicol, when administered along with testosterone propionate (low dose) prevented the testosterone-stimulated activities of cytochrome oxidase and alpha-GPDH.
...
PMID:Influence of thyroid hormones and testosterone on the activities of hepatic mitochondrial enzymes in the Indian garden lizard, Calotes versicolor. 283 60

In vivo administration of L-thyroxine (L-T4) in Anabas testudineus, while significantly stimulated the activities of cytochrome c oxidase and alpha-glycerophosphate dehydrogenase (alpha-GPDH), inhibited glucose-6-phosphate dehydrogenase (G-6-PDH), cytosolic and mitochondrial malate dehydrogenase (cyt. MDH; mit. MDH), and Mg2+ DNP-dependent adenosine triphosphatase (Mg2+ ATPase) activities. The activities of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), and catalase remained unaltered after L-T4 treatment. Administration of protein synthesis inhibitors such as actinomycin D, while significantly inhibited cytochrome oxidase, alpha-GPDH, catalase, SDH, and Mg2+ ATPase activities, did not change LDH, cyt. MDH, and mit. MDH activities. Chloramphenicol injection significantly stimulated cytochrome oxidase, alpha-GPDH, and G-6-PDH activities. Simultaneous injections of actinomycin D or chloramphenicol with 3,5,3'-triiodo-L-thyronine (L-T3) or L-T4 prevented the effects of thyroid hormones on enzyme activities, when compared to the respective controls.
...
PMID:Oxidative metabolism in a teleost, Anabas testudineus Bloch: effect of thyroid hormones on hepatic enzyme activities. 292 Sep 3

The dynamic changes in the CAP, SP and EP in the scale media were examined with single micropipet during anoxia and reventilation with oxygen. Also, the morphologic changes in the IHC, OHC and synapse were observed in this experiment. It was found that the amplitude of the SP and EP values declined with alteration in polarity of these value. The changes in polarity and amplitude of the SP followed the changes of CAP threshold induced by anoxia. The histologic examinations revealed no evidence of acetylcholinesterase (AChE) alteration in the synapse and no succinic dehydrogenase (SDH) changes in IHC appeared. However, the activity of SDH in the OHC decreased. The results suggest that the polarity and amplitude of SP were influenced passively by the changes of EP value. In addition, the changes of SP polarity from positive to negative during anoxia is due to the loss of modulation process of OHC to IHC, while the SP polarity from negative to positive during the supply of oxygen is caused by regain of the modulation process of OHC.
...
PMID:[The changes in the summating potential and morphology in the cochlea of guinea pigs with anoxia]. 780 93

Our previous studies described that the human cricopharyngeus (CP) is composed of two neuromuscular compartments (NMCs), horizontal and oblique. The present study was designed to explore the differences in muscle fiber-type distribution between the NMCs within the human CP and to examine the oxidative capacity of the muscle fibers. Seven adult human CP muscles obtained from autopsies were stained for myofibrillar ATPase, reduced nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR), and succinic dehydrogenase (SDH) to analyze enzyme-histochemical fiber-type characteristics. Notable findings obtained from this study are as follows: (1) Different NMCs within the human CP contained different percentages of muscle fiber types. The horizontal CP (CPh) contained more slow-twitch fibers than the oblique CP (CPo). (2) Each of the NMCs was dividable histochemically into two layers or subcompartments: a slow fiber-type inner layer and a relatively fast fiber outer layer. (3) As a whole, type I fibers had higher levels of NADH-TR and SDH than type II fibers. However, in both type I and II muscle fiber types, different patterns of oxidative enzyme activity were seen. Histochemically defined fiber layers of the CP are not seen in other mammals, suggesting that CP function is more specialized in humans.
...
PMID:Muscle fiber-type distribution pattern in the human cricopharyngeus muscle. 1195 34

The modulatory efficacy of capsaicin on lung mitochondrial enzyme system with reference to mitochondrial lipid peroxidation (LPO), antioxidants, key citric acid cycle enzymes and respiratory chain enzymes during benzo(a)pyrene (B(a)P) induced lung cancer in Swiss albino mice was studied. Elevations in mitochondrial LPO along with decrements in enzymic antioxidants (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST)), non-enzymic antioxidants (reduced glutathione (GSH), vitamin C, vitamin E and vitamin A), citric acid cycle enzymes (isocitrate dehydrogenase (ICDH), alpha-ketoglutarate dehydrogenase (alpha-KDH), succinate dehydrogenase (SDH) and malate dehydrogenase (MDH)), and respiratory chain enzymes (NADH dehydrogenase and Cytochrome c oxidase) were observed in B(a)P (50mg/kg body weight) administered animals. CAP (10mg/kg body weight) pretreatment decreased lung mitochondrial LPO and augmented the activities of enzymic, non-enzymic antioxidants, citric acid cycle enzymes and respiratory chain enzymes to near normalcy revealing its chemoprotective function during B(a)P induced lung cancer.
...
PMID:Stabilization of pulmonary mitochondrial enzyme system by capsaicin during benzo(a)pyrene induced experimental lung cancer. 1802 35

Collecting energy for photosystem II is facilitated by several pigments, xanthophylls and chlorophylls, embedded in the light harvesting complex II (LHCII). One xanthophyll, violaxanthin (Vio), is loosely bound at a site close to a chlorophyll b (Chl). No final answer has yet been found for the role of this specific xanthophyll. We study the electronic structure of Vio in the presence of Chl and under the influence of the LHCII environment, represented by a point charge field (PCF). We compare the capability of the long range corrected density functional theory (DFT) functional CAM-B3LYP to B3LYP for the modeling of the UV/vis spectrum of the Vio+Chl pair. CAM-B3LYP was reported to allow for a very realistic reproduction of bond length alternation of linear polyenes, which has considerable impact on the carotenoid structure and spectrum. To account for the influence of the LHCII environment, the chromophore geometries are optimized using an ONIOM(DFT/6-31G(d):PM6) scheme. Our calculations show that the energies of the locally excited states are almost unaffected by the presence of the partner chromophore or the PCF. There are, however, indications for excitonic coupling of the Chl Soret band and Vio. We propose that Vio may accept energy from blue-light excited Chl.
...
PMID:Modeling of a violaxanthin-chlorophyll b chromophore pair in its LHCII environment using CAM-B3LYP. 2230 26

It is proposed that xanthophylls, and carotenoids in general, may assist in energy transfer from the chlorophyll Soret band to the Q band. Ground-state (1Ag ) and excited-state (1Bu ) optimizations of violaxanthin (Vx) and zeaxanthin (Zx) are performed in an environment mimicking the light-harvesting complex II (LHCII), including the closest chlorophyll b molecule (Chl). Time-dependent density functional theory (TD-DFT, CAM-B3LYP functional) is used in combination with a semi-empirical description to obtain the excited-state geometries, supported by additional DFT/multireference configuration interaction calculations, with and without point charges representing LHCII. In the ground state, Vx and Zx show similar properties. At the 1Bu minimum, the energy of the Zx 1Bu state is below the Chl Q band, in contrast to Vx. Both Vx and Zx may act as acceptors of Soret-state energy; transfer to the Q band seems to be favored for Vx. These findings suggest that carotenoids may generally mediate Soret-to-Q energy flow in LHCII.
...
PMID:Carotenoids as a shortcut for chlorophyll Soret-to-Q band energy flow. 2517 82


1

---