Oxidative phosphorylation or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing the chemical energy stored within the nutrients in order to produce adenosine triphosphate (ATP). In eukaryotes, this takes place inside mitochondria. Almost all aerobic organisms carry out oxidative phosphorylation. This pathway is so pervasive because it releases more energy than alternative fermentation processes such as anaerobic glycolysis.
Respiratory complex I, EC 7.1.1.2 is the first large protein complex of the respiratory chains of many organisms from bacteria to humans. It catalyzes the transfer of electrons from NADH to coenzyme Q10 (CoQ10) and translocates protons across the inner mitochondrial membrane in eukaryotes or the plasma membrane of bacteria.
5' AMP-activated protein kinase or AMPK or 5' adenosine monophosphate-activated protein kinase is an enzyme that plays a role in cellular energy homeostasis, largely to activate glucose and fatty acid uptake and oxidation when cellular energy is low. It belongs to a highly conserved eukaryotic protein family and its orthologues are SNF1 in yeast, and SnRK1 in plants. It consists of three proteins (subunits) that together make a functional enzyme, conserved from yeast to humans. It is expressed in a number of tissues, including the liver, brain, and skeletal muscle. In response to binding AMP and ADP, the net effect of AMPK activation is stimulation of hepatic fatty acid oxidation, ketogenesis, stimulation of skeletal muscle fatty acid oxidation and glucose uptake, inhibition of cholesterol synthesis, lipogenesis, and triglyceride synthesis, inhibition of adipocyte lipogenesis, inhibition of adipocyte lipolysis, and modulation of insulin secretion by pancreatic beta-cells.
Succinate dehydrogenase (SDH) or succinate-coenzyme Q reductase (SQR) or respiratory complex II is an enzyme complex, found in many bacterial cells and in the inner mitochondrial membrane of eukaryotes. It is the only enzyme that participates in both the citric acid cycle and the electron transport chain. Histochemical analysis showing high succinate dehydrogenase in muscle demonstrates high mitochondrial content and high oxidative potential.
In biochemistry, flavin adenine dinucleotide (FAD) is a redox-active coenzyme associated with various proteins, which is involved with several enzymatic reactions in metabolism. A flavoprotein is a protein that contains a flavin group, which may be in the form of FAD or flavin mononucleotide (FMN). Many flavoproteins are known: components of the succinate dehydrogenase complex, α-ketoglutarate dehydrogenase, and a component of the pyruvate dehydrogenase complex.
The branched-chain α-ketoacid dehydrogenase complex is a multi-subunit complex of enzymes that is found on the mitochondrial inner membrane. This enzyme complex catalyzes the oxidative decarboxylation of branched, short-chain alpha-ketoacids. BCKDC is a member of the mitochondrial α-ketoacid dehydrogenase complex family comprising pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase, key enzymes that function in the Krebs cycle.
Glutaric acidemia type 2 is an autosomal recessive metabolic disorder that is characterised by defects in the ability of the body to use proteins and fats for energy. Incompletely processed proteins and fats can build up, leading to a dangerous chemical imbalance called acidosis.
Succinate dehydrogenase complex, subunit A, flavoprotein variant is a protein that in humans is encoded by the SDHA gene. This gene encodes a major catalytic subunit of succinate-ubiquinone oxidoreductase, a complex of the mitochondrial respiratory chain. The complex is composed of four nuclear-encoded subunits and is localized in the mitochondrial inner membrane. SDHA contains the FAD binding site where succinate is deprotonated and converted to fumarate. Mutations in this gene have been associated with a form of mitochondrial respiratory chain deficiency known as Leigh Syndrome. A pseudogene has been identified on chromosome 3q29. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.
cAMP receptor protein is a regulatory protein in bacteria. CRP protein binds cAMP, which causes a conformational change that allows CRP to bind tightly to a specific DNA site in the promoters of the genes it controls. CRP then activates transcription through direct protein–protein interactions with RNA polymerase.
Glutaryl-CoA dehydrogenase (GCDH) is an enzyme encoded by the GCDH gene on chromosome 19. The protein belongs to the acyl-CoA dehydrogenase family (ACD). It catalyzes the oxidative decarboxylation of glutaryl-CoA to crotonyl-CoA and carbon dioxide in the degradative pathway of L-lysine, L-hydroxylysine, and L-tryptophan metabolism. It uses electron transfer flavoprotein as its electron acceptor. The enzyme exists in the mitochondrial matrix as a homotetramer of 45-kD subunits. Mutations in this gene result in the metabolic disorder glutaric aciduria type 1, which is also known as glutaric acidemia type I. Alternative splicing of this gene results in multiple transcript variants.
6-Phosphogluconate dehydrogenase (6PGD) is an enzyme in the pentose phosphate pathway. It forms ribulose 5-phosphate from 6-phosphogluconate:
Glycerol-3-phosphate dehydrogenase (GPDH) is an enzyme that catalyzes the reversible redox conversion of dihydroxyacetone phosphate to sn-glycerol 3-phosphate.
Formate dehydrogenases are a set of enzymes that catalyse the oxidation of formate to carbon dioxide, donating the electrons to a second substrate, such as NAD+ in formate:NAD+ oxidoreductase (EC 1.2.1.2) or to a cytochrome in formate:ferricytochrome-b1 oxidoreductase (EC 1.2.2.1).
Electron-transferring-flavoprotein dehydrogenase is an enzyme that transfers electrons from electron-transferring flavoprotein in the mitochondrial matrix, to the ubiquinone pool in the inner mitochondrial membrane. It is part of the electron transport chain. The enzyme is found in both prokaryotes and eukaryotes and contains a flavin and FE-S cluster. In humans, it is encoded by the ETFDH gene. Deficiency in ETF dehydrogenase causes the human genetic disease multiple acyl-CoA dehydrogenase deficiency.
The human ETFA gene encodes the Electron-transfer-flavoprotein, alpha subunit, also known as ETF-α. Together with Electron-transfer-flavoprotein, beta subunit, encoded by the 'ETFB' gene, it forms the heterodimericElectron transfer flavoprotein (ETF). The native ETF protein contains one molecule of FAD and one molecule of AMP, respectively.
The human ETFB gene encodes the Electron-transfer-flavoprotein, beta subunit, also known as ETF-β. Together with Electron-transfer-flavoprotein, alpha subunit, encoded by the 'ETFA' gene, it forms the heterodimeric Electron transfer flavoprotein (ETF). The native ETF protein contains one molecule of FAD and one molecule of AMP, respectively.
Electron transfer flavoprotein-ubiquinone oxidoreductase, mitochondrial is an enzyme that in humans is encoded by the ETFDH gene. This gene encodes a component of the electron-transfer system in mitochondria and is essential for electron transfer from a number of mitochondrial flavin-containing dehydrogenases to the main respiratory chain.
In molecular biology, the FAD dependent oxidoreductase family of proteins is a family of FAD dependent oxidoreductases. Members of this family include Glycerol-3-phosphate dehydrogenase EC 1.1.99.5, Sarcosine oxidase beta subunit EC 1.5.3.1, D-amino-acid dehydrogenase EC 1.4.99.1, D-aspartate oxidase EC 1.4.3.1.
Flavocytochrome c sulfide dehydrogenase, also known as Sulfide-cytochrome-c reductase (flavocytochrome c) (EC 1.8.2.3), is an enzyme with systematic name hydrogen-sulfide:flavocytochrome c oxidoreductase. It is found in sulfur-oxidising bacteria such as the purple phototrophic bacteria Allochromatium vinosum. This enzyme catalyses the following chemical reaction:
Long-chain acyl-CoA dehydrogenase is an enzyme with systematic name long-chain acyl-CoA:electron-transfer flavoprotein 2,3-oxidoreductase. This enzyme catalyses the following chemical reaction
