Oxidative phosphorylation or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy 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.
An electron transport chain (ETC) is a series of protein complexes and other molecules that transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples this electron transfer with the transfer of protons (H+ ions) across a membrane. Many of the enzymes in the electron transport chain are embedded within the membrane.
Malate dehydrogenase (EC 1.1.1.37) (MDH) is an enzyme that reversibly catalyzes the oxidation of malate to oxaloacetate using the reduction of NAD+ to NADH. This reaction is part of many metabolic pathways, including the citric acid cycle. Other malate dehydrogenases, which have other EC numbers and catalyze other reactions oxidizing malate, have qualified names like malate dehydrogenase (NADP+).
sn-Glycerol 3-phosphate is the organic ion with the formula HOCH2CH(OH)CH2OPO32-. It is one of two stereoisomers of the ester of dibasic phosphoric acid (HOPO32-) and glycerol. It is a component of bacterial and eukaryotic glycerophospholipids. From a historical reason, it is also known as L-glycerol 3-phosphate, D-glycerol 1-phosphate, L-α-glycerophosphoric acid.
The glycerol-3-phosphate shuttle is a mechanism used in skeletal muscle and the brain that regenerates NAD+ from NADH, a by-product of glycolysis. NADH is a reducing equivalent that stores electrons generated in the cytoplasm during glycolysis. NADH must be transported into the mitochondria to enter the oxidative phosphorylation pathway. However, the inner mitochondrial membrane is impermeable to NADH and only contains a transport system for NAD+. Depending on the type of tissue either the glycerol-3-phosphate shuttle pathway or the malate–aspartate shuttle pathway is used to transport electrons from cytoplasmic NADH into the mitochondria.
2,4 Dienoyl-CoA reductase also known as DECR1 is an enzyme which in humans is encoded by the DECR1 gene which resides on chromosome 8. This enzyme catalyzes the following reactions
Glycerol-3-phosphate dehydrogenase (GPDH) is an enzyme that catalyzes the reversible redox conversion of dihydroxyacetone phosphate to sn-glycerol 3-phosphate.
In enzymology, a glycerol-3-phosphate dehydrogenase [NAD(P)+] (EC 1.1.1.94) is an enzyme that catalyzes the chemical reaction
In enzymology, a malate oxidase (EC 1.1.3.3) is an enzyme that catalyzes the chemical reaction
In enzymology, a quinoprotein glucose dehydrogenase is an enzyme that catalyzes the chemical reaction
In enzymology, a NAD(P)H dehydrogenase (quinone) (EC 1.6.5.2) is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphoribosylanthranilate isomerase (PRAI) is an enzyme that catalyzes the third step of the synthesis of the amino acid tryptophan.
The enzyme glycerophosphodiester phosphodiesterase ({EC 3.1.4.46) catalyzes the reaction
Butyryl-CoA is an organic coenzyme A-containing derivative of butyric acid. It is a natural product found in many biological pathways, such as fatty acid metabolism, fermentation, and 4-aminobutanoate (GABA) degradation. It mostly participates as an intermediate, a precursor to and converted from crotonyl-CoA. This interconversion is mediated by butyryl-CoA dehydrogenase.
In enzymology, a CDP-diacylglycerol—glycerol-3-phosphate 3-phosphatidyltransferase is an enzyme that catalyzes the chemical reaction
Morpheeins are proteins that can form two or more different homo-oligomers, but must come apart and change shape to convert between forms. The alternate shape may reassemble to a different oligomer. The shape of the subunit dictates which oligomer is formed. Each oligomer has a finite number of subunits (stoichiometry). Morpheeins can interconvert between forms under physiological conditions and can exist as an equilibrium of different oligomers. These oligomers are physiologically relevant and are not misfolded protein; this distinguishes morpheeins from prions and amyloid. The different oligomers have distinct functionality. Interconversion of morpheein forms can be a structural basis for allosteric regulation, an idea noted many years ago, and later revived. A mutation that shifts the normal equilibrium of morpheein forms can serve as the basis for a conformational disease. Features of morpheeins can be exploited for drug discovery. The dice image represents a morpheein equilibrium containing two different monomeric shapes that dictate assembly to a tetramer or a pentamer. The one protein that is established to function as a morpheein is porphobilinogen synthase, though there are suggestions throughout the literature that other proteins may function as morpheeins.
Class 2 dihydroorotate dehydrogenases is an enzyme with systematic name (S)-dihydroorotate:quinone oxidoreductase. This enzyme catalyses the electron transfer from dihydroorotate to a quinone :
Fumarate reductase (quinol) (EC 1.3.5.4, QFR,FRD, menaquinol-fumarate oxidoreductase, quinol:fumarate reductase) is an enzyme with systematic name succinate:quinone oxidoreductase. This enzyme catalyzes the following chemical reaction:
Pyruvate dehydrogenase (quinone) (EC 1.2.5.1, pyruvate dehydrogenase, pyruvic dehydrogenase, pyruvic (cytochrome b1) dehydrogenase, pyruvate:ubiquinone-8-oxidoreductase, pyruvate oxidase (ambiguous)) is an enzyme with systematic name pyruvate:ubiquinone oxidoreductase. This enzyme catalyses the following chemical reaction
D-amino acid dehydrogenase (quinone) (EC 1.4.5.1, DadA) is an enzyme with systematic name D-amino acid:quinone oxidoreductase (deaminating). This enzyme catalyses the following chemical reaction
