Succinate Cytochrome c Oxidoreductase
Electron Transport Complex III
Sulfite Dehydrogenase
Cytochrome c Group
Cytochrome Reductases
Antimycin A
Succinic Acid
Cytochrome b Group
Electron Transport
Succinates
Cytochromes c
Succinate Dehydrogenase
Cytochromes
Oxidation-Reduction
Mitochondria
Cytochromes c1
Quinone Reductases
Electron Transport Complex IV
Inhibition of fumarate reductase in Leishmania major and L. donovani by chalcones. (1/61)
Our previous studies have shown that chalcones exhibit potent antileishmanial and antimalarial activities in vitro and in vivo. Preliminary studies showed that these compounds destroyed the ultrastructure of Leishmania parasite mitochondria and inhibited the respiration and the activity of mitochondrial dehydrogenases of Leishmania parasites. The present study was designed to further investigate the mechanism of action of chalcones, focusing on the parasite respiratory chain. The data show that licochalcone A inhibited the activity of fumarate reductase (FRD) in the permeabilized Leishmania major promastigote and in the parasite mitochondria, and it also inhibited solubilized FRD and a purified FRD from L. donovani. Two other chalcones, 2,4-dimethoxy-4'-allyloxychalcone (24m4ac) and 2,4-dimethoxy-4'-butoxychalcone (24mbc), also exhibited inhibitory effects on the activity of solubilized FRD in L. major promastigotes. Although licochalcone A inhibited the activities of succinate dehydrogenase (SDH), NADH dehydrogenase (NDH), and succinate- and NADH-cytochrome c reductases in the parasite mitochondria, the 50% inhibitory concentrations (IC(50)) of licochalcone A for these enzymes were at least 20 times higher than that for FRD. The IC(50) of licochalcone A for SDH and NDH in human peripheral blood mononuclear cells were at least 70 times higher than that for FRD. These findings indicate that FRD, one of the enzymes of the parasite respiratory chain, might be the specific target for the chalcones tested. Since FRD exists in the Leishmania parasite and does not exist in mammalian cells, it could be an excellent target for antiprotozoal drugs. (+info)Isoprenoid biosynthesis is not compromised in a Zellweger syndrome mouse model. (2/61)
Because several studies indicated that peroxisomes are important for the biosynthesis of isoprenoids, we wanted to investigate whether a reduced availability of isoprenoids could be one of the pathogenic factors contributing to the severe phenotype of the Pex5(-/-) mouse, a model for Zellweger syndrome. Total cholesterol was determined in plasma, brain and liver of newborn mice. In none of these tissues a significant difference was observed between Pex5(-/-) and wild type or heterozygous mice. The hepatic ubiquinone content was found to be even higher in Pex5(-/-) mice as compared to wild type or heterozygous littermates. To investigate whether the Pex5(-/-) fetuses are able to synthesise their own isoprenoids, fibroblasts derived from these mice were incubated with radiolabeled mevalonolactone as a substrate for isoprenoid synthesis. No significant difference was observed between the cholesterol production rates of Pex5(-/-) and normal fibroblasts. Our results show that there is no deficiency of isoprenoids in newborn Pex5(-/-) mice, excluding the possibility that a lack of these compounds is a determinant factor in the development of the disease state before birth. (+info)Nitric oxide inhibits mitochondrial NADH:ubiquinone reductase activity through peroxynitrite formation. (3/61)
This study was aimed at assessing the effects of long-term exposure to NO of respiratory activities in mitochondria from different tissues (with different ubiquinol contents), under conditions that either promote or prevent the formation of peroxynitrite. Mitochondria and submitochondrial particles isolated from rat heart, liver and brain were exposed either to a steady-state concentration or to a bolus addition of NO. NO induced the mitochondrial production of superoxide anions, hydrogen peroxide and peroxynitrite, the latter shown by nitration of mitochondrial proteins. Long-term incubation of mitochondrial membranes with NO resulted in a persistent inhibition of NADH:cytochrome c reductase activity, interpreted as inhibition of NADH:ubiquinone reductase (Complex I) activity, whereas succinate:cytochrome c reductase activity, including Complex II and Complex III electron transfer, remained unaffected. This selective effect of NO and derived species was partially prevented by superoxide dismutase and uric acid. In addition, peroxynitrite mimicked the effect of NO, including tyrosine nitration of some Complex I proteins. These results seem to indicate that the inhibition of NADH:ubiquinone reductase (Complex I) activity depends on the NO-induced generation of superoxide radical and peroxynitrite and that Complex I is selectively sensitive to peroxynitrite. Inhibition of Complex I activity by peroxynitrite may have critical implications for energy supply in tissues such as the brain, whose mitochondrial function depends largely on the channelling of reducing equivalents through Complex I. (+info)Coenzyme Q releases the inhibitory effect of free fatty acids on mitochondrial glycerophosphate dehydrogenase. (4/61)
Data presented in this paper show that the size of the endogenous coenzyme Q (CoQ) pool is not a limiting factor in the activation of mitochondrial glycerophosphate-dependent respiration by exogenous CoQ(3), since successive additions of succinate and NADH to brown adipose tissue mitochondria further increase the rate of oxygen uptake. Because the inhibition of glycerophosphate-dependent respiration by oleate was eliminated by added CoQ(3), our data indicate that the activating effect of CoQ(3) is related to the release of the inhibitory effect of endogenous free fatty acids (FFA). Both the inhibitory effect of FFA and the activating effect of CoQ(3) could be demonstrated only for glycerophosphate-dependent respiration, while succinate- or NADH-dependent respiration was not affected. The presented data suggest differences between mitochondrial glycerophosphate dehydrogenase and succinate or NADH dehydrogenases in the transfer of reducing equivalents to the CoQ pool. (+info)Cellular and subcellular localization of enzymes of arginine metabolism in rat kidney. (5/61)
Rat kidneys extract citrulline derived from the intestinal metabolism of glutamine and convert it stoichiometrically into arginine. This pathway constitutes the major endogenous source of arginine. We investigated the localization of enzymes of arginine synthesis, argininosuccinate synthase and lyase, and of breakdown, arginase and ornithine aminotransferase, in five regions of rat kidney, in cortical tubule fractions and in subcellular fractions of cortex. Argininosuccinate synthase and lyase were found almost exclusively in cortex. Arginase and ornithine aminotransferase were found in inner cortex and outer medulla. Since cortical tissue primarily consists of proximal convoluted and straight tubules, distal tubules and glomeruli, we prepared cortical tubule fragments by collagenase digestion of cortices and fractionated them on a Percoll gradient. Argininosuccinate synthase and lyase were found to be markedly enriched in proximal convoluted tubules, whereas less than 10% of arginase and ornithine aminotransferase, were recovered in this fraction. Arginine production from citrulline was also enriched in proximal convoluted tubules. Subcellular fractionation of kidney cortex revealed that argininosuccinate synthase and lyase are cytosolic. We therefore conclude that arginine synthesis occurs in the cytoplasm of the cells of the proximal convoluted tubule. (+info)Sialyltransferase activity and hepatic tumor growth in a nude mouse model of colorectal cancer metastases. (6/61)
Sialyltransferase activity (EC 2.4.99.6) was measured in the microsomal fraction of colorectal cancer cell lines using an assay based on the incorporation of [14C]CMP-sialic acid into asialofetuin. In the poorly differentiated lines MIP101 and Clone A, sialyltransferase activity had a Vmax of 0.36 and 0.31 nmol/mg protein/h, respectively, while the moderately differentiated to well-differentiated cell lines HT-29, CCL188, and CX-1 had Vmaxs of 2.46, 1.05, and 1.24 nmol/mg protein/h, respectively. All cell lines tested had a Km of 15.4 (+/- 0.7)(SD) mumol/liter. The better differentiated cells had higher levels of sialyltransferase activity, which correlated with their higher levels of sialic acid and their enhanced ability to form liver metastases in the nude mouse following intrasplenic injection compared to the poorly differentiated cell lines. Treatment of the cell lines with KI-8110, a CMP-sialic acid derivative which prevents incorporation of sialic acid into glycoconjugates, resulted in reduced formation of hepatic metastases by the colorectal carcinoma cell lines in the nude mouse model. It is suggested that reduced sialylation of adhesion molecules such as carcinoembryonic antigen may change the biology of the tumor cell, one consequence of which is the prevention of implantation of the cells into distant sites, resulting in a reduced incidence of metastases. (+info)The interaction of platinum antitumour drugs with mouse liver mitochondria. (7/61)
A study was undertaken to determine if cis-DDP and its second generation derivatives produced effects on mouse liver mitochondria, and if any of the observed effects could be correlated with the nephrotoxicity of the drugs. Although changes were observed in mitochondrial morphology, enzyme activity, Ca2+ influx, terbium binding and surface potential, no specific effect was correlated with nephrotoxicity. cis-DDP produced marked changes in mitochondrial morphology; electron probe analysis showed binding of the drug to the mitochondria. Inhibition of complex I and II activity of the respiratory chain and an ionic-strength-dependent effect on Tb3+ (a Ca2+ analogue) fluorescence were observed. The non-nephrotoxic derivatives, CHIP and tetraplatin, also produced significant changes in morphology. Treatment with these derivatives also produced decreases in mitochondrial enzyme activity, but the effect on terbium binding had an ionic-strength dependence which was inverse to that observed with cis-DDP. The tetravalent compounds also had a notable effect on mitochondrial surface potential. Carboplatin had an effect on morphology and Ca2+ influx and it inhibited the respiratory enzymes, although in a manner different from that observed with cis-DDP. Carboplatin had a minimal effect on terbium binding. It is evident that if the platinum drugs enter a cell to exert their action at the nuclear level, they will also depress mitochondrial function. The observed effects did not correlate with nephrotoxicity but, since all four compounds significantly altered mitochondrial structure and function, they may be related to the cytotoxicity of the drug. (+info)Inhibition of brain energy metabolism by the alpha-keto acids accumulating in maple syrup urine disease. (8/61)
Neurological dysfunction is a common finding in patients with maple syrup urine disease (MSUD). However, the mechanisms underlying the neuropathology of brain damage in this disorder are poorly known. In the present study, we investigated the effect of the in vitro effect of the branched chain alpha-keto acids (BCKA) accumulating in MSUD on some parameters of energy metabolism in cerebral cortex of rats. [14CO(2)] production from [14C] acetate, glucose uptake and lactate release from glucose were evaluated by incubating cortical prisms from 30-day-old rats in Krebs-Ringer bicarbonate buffer, pH 7.4, in the absence (controls) or presence of 1-5 mM of alpha-ketoisocaproic acid (KIC), alpha-keto-beta-methylvaleric acid (KMV) or alpha-ketoisovaleric acid (KIV). All keto acids significantly reduced 14CO(2) production by around 40%, in contrast to lactate release and glucose utilization, which were significantly increased by the metabolites by around 42% in cortical prisms. Furthermore, the activity of the respiratory chain complex I-III was significantly inhibited by 60%, whereas the other activities of the electron transport chain, namely complexes II, II-III, III and IV, as well as succinate dehydrogenase were not affected by the keto acids. The results indicate that the major metabolites accumulating in MSUD compromise brain energy metabolism by blocking the respiratory chain. We presume that these findings may be of relevance to the understanding of the pathophysiology of the neurological dysfunction of MSUD patients. (+info)Succinate cytochrome c oxidoreductase, also known as complex II or succinate-Q-reductase, is an enzyme complex in the electron transport chain that plays a crucial role in cellular respiration. It is located in the inner mitochondrial membrane of eukaryotic cells and the cytoplasmic membrane of prokaryotic cells.
Complex II consists of four subunits ( flavoprotein, iron-sulfur protein, and two cytochromes ) that catalyze the oxidation of succinate to fumarate, reducing FAD to FADH2 in the process. The FADH2 then transfers its electrons to the iron-sulfur protein and subsequently to ubiquinone (Q), reducing it to ubiquinol (QH2). This transfer of electrons drives the proton pumping across the membrane, contributing to the formation of a proton gradient that is used for ATP synthesis.
Complex II is unique among the electron transport chain complexes because it can operate independently of the other complexes and does not span the entire width of the inner mitochondrial membrane. It also plays a role in the regulation of reactive oxygen species (ROS) production, making it an important target for understanding various diseases, including neurodegenerative disorders and cancer.
Electron Transport Complex III, also known as cytochrome bc1 complex or ubiquinol-cytochrome c reductase, is a protein complex located in the inner mitochondrial membrane of eukaryotic cells and the cytoplasmic membrane of prokaryotic cells. It plays a crucial role in the electron transport chain (ETC), a series of complexes that generate energy in the form of ATP through a process called oxidative phosphorylation.
In ETC, Electron Transport Complex III accepts electrons from ubiquinol and transfers them to cytochrome c. This electron transfer is coupled with the translocation of protons (H+ ions) across the membrane, creating an electrochemical gradient. The energy stored in this gradient drives the synthesis of ATP by ATP synthase.
Electron Transport Complex III consists of several subunits, including cytochrome b, cytochrome c1, and the Rieske iron-sulfur protein. These subunits work together to facilitate the electron transfer and proton translocation processes.
Sulfite dehydrogenase is an enzyme found in various organisms, including bacteria, fungi, and humans. It plays a crucial role in the metabolism of sulfur-containing compounds. The medical definition of 'sulfite dehydrogenase' is:
An enzyme (EC 1.8.2.1) that catalyzes the oxidation of sulfite to sulfate, using a variety of electron acceptors such as molecular oxygen, ferricytochrome c, or other quinones. In humans, there are two main types of sulfite dehydrogenases: one is mitochondrial (found in the inner mitochondrial membrane) and uses flavin adenine dinucleotide (FAD) as a cofactor, while the other is cytosolic and contains molybdopterin as a cofactor.
Deficiency or dysfunction of sulfite dehydrogenase can lead to an accumulation of sulfites in the body, which may result in several health issues, such as neurological disorders, respiratory problems, and cardiovascular diseases. Some individuals might have genetic mutations affecting the enzyme's function, leading to conditions like molybdenum cofactor deficiency or isolated sulfite oxidase deficiency. These rare inherited metabolic disorders can cause severe neurological symptoms and developmental delays.
Cytochrome c is a small protein that is involved in the electron transport chain, a key part of cellular respiration in which cells generate energy in the form of ATP. Cytochrome c contains a heme group, which binds to and transports electrons. The cytochrome c group refers to a class of related cytochromes that have similar structures and functions. These proteins are found in the mitochondria of eukaryotic cells (such as those of plants and animals) and in the inner membranes of bacteria. They play a crucial role in the production of energy within the cell, and are also involved in certain types of programmed cell death (apoptosis).
Cytochrome reductases are a group of enzymes that play a crucial role in the electron transport chain, a process that occurs in the mitochondria of cells and is responsible for generating energy in the form of ATP (adenosine triphosphate). Specifically, cytochrome reductases are responsible for transferring electrons from one component of the electron transport chain to another, specifically to cytochromes.
There are several types of cytochrome reductases, including NADH dehydrogenase (also known as Complex I), succinate dehydrogenase (also known as Complex II), and ubiquinone-cytochrome c reductase (also known as Complex III). These enzymes help to facilitate the flow of electrons through the electron transport chain, which is essential for the production of ATP and the maintenance of cellular homeostasis.
Defects in cytochrome reductases can lead to a variety of mitochondrial diseases, which can affect multiple organ systems and may be associated with symptoms such as muscle weakness, developmental delays, and cardiac dysfunction.
Antimycin A is an antibiotic substance produced by various species of Streptomyces bacteria. It is known to inhibit the electron transport chain in mitochondria, which can lead to cellular dysfunction and death. Antimycin A has been used in research to study the mechanisms of cellular respiration and oxidative phosphorylation.
In a medical context, antimycin A is not used as a therapeutic agent due to its toxicity to mammalian cells. However, it may be used in laboratory settings to investigate various biological processes or to develop new therapies for diseases related to mitochondrial dysfunction.
Succinic acid, also known as butanedioic acid, is an organic compound with the chemical formula HOOC(CH2)2COOH. It is a white crystalline powder that is soluble in water and has a slightly acerbic taste. In medicine, succinic acid is not used as a treatment for any specific condition. However, it is a naturally occurring substance found in the body and plays a role in the citric acid cycle, which is a key process in energy production within cells. It can also be found in some foods and is used in the manufacturing of various products such as pharmaceuticals, resins, and perfumes.
Cytochrome b is a type of cytochrome, which is a class of proteins that contain heme as a cofactor and are involved in electron transfer. Cytochromes are classified based on the type of heme they contain and their absorption spectra.
The cytochrome b group includes several subfamilies of cytochromes, including cytochrome b5, cytochrome b2, and cytochrome bc1 (also known as complex III). These cytochromes are involved in various biological processes, such as fatty acid desaturation, steroid metabolism, and the electron transport chain.
The electron transport chain is a series of protein complexes in the inner mitochondrial membrane that generates most of the ATP (adenosine triphosphate) required for cellular energy production. Cytochrome bc1 is a key component of the electron transport chain, where it functions as a dimer and catalyzes the transfer of electrons from ubiquinol to cytochrome c while simultaneously pumping protons across the membrane. This creates an electrochemical gradient that drives ATP synthesis.
Deficiencies or mutations in cytochrome b genes can lead to various diseases, such as mitochondrial disorders and cancer.
The Electron Transport Chain (ETC) is a series of complexes in the inner mitochondrial membrane that are involved in the process of cellular respiration. It is the final pathway for electrons derived from the oxidation of nutrients such as glucose, fatty acids, and amino acids to be transferred to molecular oxygen. This transfer of electrons drives the generation of a proton gradient across the inner mitochondrial membrane, which is then used by ATP synthase to produce ATP, the main energy currency of the cell.
The electron transport chain consists of four complexes (I-IV) and two mobile electron carriers (ubiquinone and cytochrome c). Electrons from NADH and FADH2 are transferred to Complex I and Complex II respectively, which then pass them along to ubiquinone. Ubiquinone then transfers the electrons to Complex III, which passes them on to cytochrome c. Finally, cytochrome c transfers the electrons to Complex IV, where they combine with oxygen and protons to form water.
The transfer of electrons through the ETC is accompanied by the pumping of protons from the mitochondrial matrix to the intermembrane space, creating a proton gradient. The flow of protons back across the inner membrane through ATP synthase drives the synthesis of ATP from ADP and inorganic phosphate.
Overall, the electron transport chain is a crucial process for generating energy in the form of ATP in the cell, and it plays a key role in many metabolic pathways.
Succinates, in a medical context, most commonly refer to the salts or esters of succinic acid. Succinic acid is a dicarboxylic acid that is involved in the Krebs cycle, which is a key metabolic pathway in cells that generates energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins.
Succinates can also be used as a buffer in medical solutions and as a pharmaceutical intermediate in the synthesis of various drugs. In some cases, succinate may be used as a nutritional supplement or as a component of parenteral nutrition formulations to provide energy and help maintain acid-base balance in patients who are unable to eat normally.
It's worth noting that there is also a condition called "succinic semialdehyde dehydrogenase deficiency" which is a genetic disorder that affects the metabolism of the amino acid gamma-aminobutyric acid (GABA). This condition can lead to an accumulation of succinic semialdehyde and other metabolic byproducts, which can cause neurological symptoms such as developmental delay, hypotonia, and seizures.
Cytochromes c are a group of small heme proteins found in the mitochondria of cells, involved in the electron transport chain and play a crucial role in cellular respiration. They accept and donate electrons during the process of oxidative phosphorylation, which generates ATP, the main energy currency of the cell. Cytochromes c contain a heme group, an organic compound that includes iron, which facilitates the transfer of electrons. The "c" in cytochromes c refers to the type of heme group they contain (cyt c has heme c). They are highly conserved across species and have been widely used as a molecular marker for evolutionary studies.
Succinate dehydrogenase (SDH) is an enzyme complex that plays a crucial role in the process of cellular respiration, specifically in the citric acid cycle (also known as the Krebs cycle) and the electron transport chain. It is located in the inner mitochondrial membrane of eukaryotic cells.
SDH catalyzes the oxidation of succinate to fumarate, converting it into a molecule of fadaquate in the process. During this reaction, two electrons are transferred from succinate to the FAD cofactor within the SDH enzyme complex, reducing it to FADH2. These electrons are then passed on to ubiquinone (CoQ), which is a mobile electron carrier in the electron transport chain, leading to the generation of ATP, the main energy currency of the cell.
SDH is also known as mitochondrial complex II because it is the second complex in the electron transport chain. Mutations in the genes encoding SDH subunits or associated proteins have been linked to various human diseases, including hereditary paragangliomas, pheochromocytomas, gastrointestinal stromal tumors (GISTs), and some forms of neurodegenerative disorders.
Cytochromes are a type of hemeprotein found in the mitochondria and other cellular membranes of organisms. They contain a heme group, which is a prosthetic group composed of an iron atom surrounded by a porphyrin ring. This structure allows cytochromes to participate in redox reactions, acting as electron carriers in various biological processes.
There are several types of cytochromes, classified based on the type of heme they contain and their absorption spectra. Some of the most well-known cytochromes include:
* Cytochrome c: a small, mobile protein found in the inner mitochondrial membrane that plays a crucial role in the electron transport chain during cellular respiration.
* Cytochrome P450: a large family of enzymes involved in the metabolism of drugs, toxins, and other xenobiotics. They are found in various tissues, including the liver, lungs, and skin.
* Cytochrome b: a component of several electron transport chains, including those found in mitochondria, bacteria, and chloroplasts.
Cytochromes play essential roles in energy production, detoxification, and other metabolic processes, making them vital for the survival and function of living organisms.
Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."
In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).
The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.
Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.
Mitochondria are specialized structures located inside cells that convert the energy from food into ATP (adenosine triphosphate), which is the primary form of energy used by cells. They are often referred to as the "powerhouses" of the cell because they generate most of the cell's supply of chemical energy. Mitochondria are also involved in various other cellular processes, such as signaling, differentiation, and apoptosis (programmed cell death).
Mitochondria have their own DNA, known as mitochondrial DNA (mtDNA), which is inherited maternally. This means that mtDNA is passed down from the mother to her offspring through the egg cells. Mitochondrial dysfunction has been linked to a variety of diseases and conditions, including neurodegenerative disorders, diabetes, and aging.
Cytochrome c1 is a protein that is a part of the electron transport chain in the inner mitochondrial membrane. It is a component of Complex III, also known as the cytochrome bc1 complex. Cytochrome c1 contains a heme group and plays a role in the transfer of electrons from ubiquinol to cytochrome c during oxidative phosphorylation, which is the process by which cells generate energy in the form of ATP. Defects in cytochrome c1 can lead to mitochondrial disorders and have been implicated in the development of certain diseases, such as neurodegenerative disorders and cancer.
Quinone reductases are a group of enzymes that catalyze the reduction of quinones to hydroquinones, using NADH or NADPH as an electron donor. This reaction is important in the detoxification of quinones, which are potentially toxic compounds produced during the metabolism of certain drugs, chemicals, and endogenous substances.
There are two main types of quinone reductases: NQO1 (NAD(P)H:quinone oxidoreductase 1) and NQO2 (NAD(P)H:quinone oxidoreductase 2). NQO1 is a cytosolic enzyme that can reduce a wide range of quinones, while NQO2 is a mitochondrial enzyme with a narrower substrate specificity.
Quinone reductases have been studied for their potential role in cancer prevention and treatment, as they may help to protect cells from oxidative stress and DNA damage caused by quinones and other toxic compounds. Additionally, some quinone reductase inhibitors have been developed as chemotherapeutic agents, as they can enhance the cytotoxicity of certain drugs that require quinone reduction for activation.
Electron Transport Complex IV is also known as Cytochrome c oxidase. It is the last complex in the electron transport chain, located in the inner mitochondrial membrane of eukaryotic cells and the plasma membrane of prokaryotic cells. This complex contains 13 subunits, two heme groups (a and a3), and three copper centers (A, B, and C).
In the electron transport chain, Complex IV receives electrons from cytochrome c and transfers them to molecular oxygen, reducing it to water. This process is accompanied by the pumping of protons across the membrane, contributing to the generation of a proton gradient that drives ATP synthesis via ATP synthase (Complex V). The overall reaction catalyzed by Complex IV can be summarized as follows:
4e- + 4H+ + O2 → 2H2O
Defects in Cytochrome c oxidase can lead to various diseases, including mitochondrial encephalomyopathies and neurodegenerative disorders.
Mitochondrial matrix
SDHD
Succinate dehydrogenase complex subunit C
List of MeSH codes (D08)
Deinococcus marmoris
List of MeSH codes (D05)
Transporter Classification Database
Electron transport chain
Mitochondrial membrane transport protein
Oxidative phosphorylation
Respiratory complex I
Green sulfur bacteria
Ferredoxin
List of EC numbers (EC 1)
Dehydrogenase
Microbial metabolism
Sulfur-reducing bacteria
Index of molecular biology articles
Citric acid cycle
Succinate dehydrogenase
List of enzymes
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MESH TREE NUMBER CHANGES - 2012 MeSH. August 19, 2011
MESH TREE NUMBER CHANGES - 2012 MeSH. August 19, 2011
MESH TREE NUMBER CHANGES - 2012 MeSH. August 19, 2011
MESH TREE NUMBER CHANGES - 2012 MeSH. August 19, 2011
MESH TREE NUMBER CHANGES - 2012 MeSH. August 19, 2011
Subunit5
- 10. Characterization of the human SDHD gene encoding the small subunit of cytochrome b (cybS) in mitochondrial succinate-ubiquinone oxidoreductase. (nih.gov)
- In line with these observations, proteomic analysis of intracellular neurofibrillary tangles from AD patients, by means of laser-capture micro-dissection, allowed the identification of many mitochondrial proteins, such as cytochrome c oxidase subunit IV isoform 1 (OxPhos complex IV), ATP synthase a, b and O subunits (OxPhos complex V) and adenine nucleotide translocase (ANT)1, 2 and 3 (carrier proteins) as component of these aggregates. (medscape.com)
- 13] who first isolated from mitochondria four enzyme multi-subunit complexes that concur on the oxidation of NADH and succinate, namely NADH-Coenzyme Q reductase (Complex I, CI), succinate-Coenzyme Q reductase (Complex II, CII), ubiquinol-cytochrome c reductase (Complex III, CIII or cytochrome bc 1 Complex) and cytochrome c oxidase (Complex IV, CIV) [14] . (researchgate.net)
- cytochrome c oxidase subunit 4I1 [Sour. (gsea-msigdb.org)
- cytochrome c oxidase subunit 6B1 [Sour. (gsea-msigdb.org)
Reductase8
- 5. [Complex II (succinate-ubiquinone reductase) deficiency]. (nih.gov)
- In the mitochondrial respiratory chain, CoQ10 is vital for the transport of electrons from complex I (NADH-ubiquinone oxidoreductase) and complex II (succinate-ubiquinone oxidoreductase) to complex III (ubiquinol-cytochrome c reductase). (nih.gov)
- Biochemical investigation in fibroblasts showed decreased activity of the CoQ dependent mitochondrial respiratory chain enzyme succinate cytochrome c reductase (complex II + III). (tau.ac.il)
- In addition, the presence of a succinate:quinone oxidoreductase:nitrate reductase supercomplex was confirmed by the co-localized succinate:nitroblue tetrazolium and methylviologen:nitrate oxidoreductase activities detected in gel and corroborated by LC-MS/MS analysis. (usuhs.edu)
- Succinate:quinone reductase catalyzes electron transfer from succinate to quinone in aerobic respiration. (bvsalud.org)
- We have isolated mutant strains of the bacterium Paracoccus denitrificans that are resistant to carboxin due to mutations in the succinate:quinone reductase. (bvsalud.org)
- His28 and His113 are the axial ligands to heme b(D) in Bacillus subtilis succinate:menaquinone reductase. (bvsalud.org)
- Molybdopterin oxidoreductase, Molydopterin dinucleotide binding domain, Respiratory nitrate reductase alpha N-terminal [Interproscan]. (ntu.edu.sg)
Mitochondrial1
- At the mitochondrial level, atovaquone, targeting the cytochrome bc 1 complex, inhibits the parasite electron transport chain and thus the dihydro-orotate dehydrogenase (DHODH) activity linked to the respiratory chain and involved in pyrimidine nucleotide biosynthesis [ 8 ]. (biomedcentral.com)
Fumarate3
- As part of the citric acid cycle, the SDH enzyme converts a compound called succinate to another compound called fumarate. (medlineplus.gov)
- Without the SDH enzyme, succinate is not converted to fumarate, and succinate builds up in cells. (medlineplus.gov)
- The enzyme has a central role in carbon and energy metabolism by catalyzing the oxidation of succinate to form fumarate coupled to the reduction of quinone in the respiratory chain. (lu.se)
Enzyme4
- The SDHC gene provides instructions for making one of four subunits of the succinate dehydrogenase (SDH) enzyme. (medlineplus.gov)
- Succinate, the compound on which the SDH enzyme acts, is an oxygen sensor in the cell and can help turn on specific pathways that stimulate cells to grow in a low-oxygen environment (hypoxia). (medlineplus.gov)
- The succinate:menaquinone reductases all contain two heme groups in the membrane anchor of the enzyme: a proximal heme (heme b(P)) located close to the negative side of the membrane and a distal heme (heme b(D)) located close to the positive side of the membrane. (bvsalud.org)
- Succinate:quinone oxidoreductase (SQR) is both a Krebs´ citric acid cycle enzyme and a component (Complex II) of the respiratory chain in aerobic cells. (lu.se)
Malate1
- All of the enzymes for the citric acid cycle are in the matrix (e.g. citrate synthase, isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, fumarase, and malate dehydrogenase) except for succinate dehydrogenase which is on the inner membrane and is part of protein complex II in the electron transport chain. (wikipedia.org)
Quinone3
- Succinate:quinone reductases are membrane-bound enzymes that catalyze electron transfer from succinate to quinone. (bvsalud.org)
- Heme b(D) is a distinctive feature of the succinate:menaquinone reductases, but the role of this heme in electron transfer to quinone has not previously been analyzed. (bvsalud.org)
- Using a B. subtilis strain which overproduces succinate:quinone oxidoreductase (respiratory complex II), we were able to improve the current response several fold using succinate as substrate. (science24.com)
Respiratory2
- Here, we have revisited recent data on the supercomplexes of Bacillus subtilis respiratory chain, by means of 1D and 2D-BN-PAGE, sucrose gradient fractionation of solubilized membranes, and mass spectrometry analysis of BN-PAGE bands detected in gel for succinate and cytochrome c oxidoreductase activities. (usuhs.edu)
- It is the terminal oxidase complex of the RESPIRATORY CHAIN and collects electrons that are transferred from the reduced CYTOCHROME C GROUP and donates them to molecular OXYGEN, which is then reduced to water. (lookformedical.com)
Membrane-spanni1
- SQR consists of a membrane-peripheral heterodimer domain (often called succinate dehydrogenase) which is tightly bound to a membrane-spanning anchor, which is a cytochrome with one or two heme groups depending on the organism. (lu.se)
Protein2
- In particular, succinate stabilizes a protein called hypoxia-inducible factor (HIF) by preventing a reaction that would allow HIF to be broken down. (medlineplus.gov)
- The excess succinate abnormally stabilizes the HIF protein, which also builds up in cells. (medlineplus.gov)
Coenzyme2
- These complexes are complex I (NADH:coenzyme Q oxidoreductase), complex II (succinate:coenzyme Q oxidoreductase), complex III (coenzyme Q: cytochrome c oxidoreductase), and complex IV (cytochrome c oxidase). (wikipedia.org)
- Coenzyme Q (CoQ, ubiquinone) and cytochrome c (cyt. (researchgate.net)
Donors1
- The effect of various electron donors (NADH, succinate and 2,3-dimethoxy-5-methyl-6-decyl- 1,4-benzoquinol ) on ROS production was tested separately in the presence or absence of Cd. (cdc.gov)
Complex II3
- 11. Succinate in dystrophic white matter: a proton magnetic resonance spectroscopy finding characteristic for complex II deficiency. (nih.gov)
- The complexes studied are Complex I (NADH:Ubiquinone oxidoreductase), Complex II (Succinate:ubiquinone oxidoreductase), Complex III (Ubiquinol:cytochrome c oxidoreductase), and Complex IV (Cytochrome c oxidase). (cdc.gov)
- An electron transport chain complex that catalyzes the transfer of electrons from SUCCINATE to CYTOCHROME C . It includes ELECTRON TRANSPORT COMPLEX II and ELECTRON TRANSPORT COMPLEX III . (nih.gov)
Bacteria1
- An FAD-dependent oxidoreductase found primarily in BACTERIA . (nih.gov)
Proteins1
- Like UQCRC1 in preventing cytochrome c from release, functions of ETC proteins beyond oxidative phosphorylation might also contribute to the pathogenesis of PD. (frontiersin.org)
Coli2
- Recently we have also showed that introduction of a cytochrome to the cytoplasmic membrane of E. coli greatly facilitated the communication between these gram-negative bacterial cells and the osmium polymers. (science24.com)
- However, the E. coli cells did not show increased succinate dehydrogenase activity nor did the operon complement a sdhCDAB defective E. coli mutant [7]. (lu.se)
Carbon1
- Cells tend to be pleomorphic if grown on media containing succinate or coccoid if grown in the presence of an alcohol as the sole carbon source. (lookformedical.com)
Domain1
- Thioredoxin domain, Pyridine nucleotide-disulphide oxidoreductase [Interproscan]. (ntu.edu.sg)
