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Oxidative phosphorylation (UK / ɒ k ˈ s ɪ d. ə. t ɪ v /, US / ˈ ɑː k. s ɪ ˌ d eɪ. t ɪ v / [1]) 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).
An example of a coupled reaction is the phosphorylation of fructose-6-phosphate to form the intermediate fructose-1,6-bisphosphate by the enzyme phosphofructokinase accompanied by the hydrolysis of ATP in the pathway of glycolysis. The resulting chemical reaction within the metabolic pathway is highly thermodynamically favorable and, as a ...
[4] [5] The speed at which ATP is produced is about 100 times that of oxidative phosphorylation. [1] Anaerobic glycolysis is thought to have been the primary means of energy production in earlier organisms before oxygen was at high concentration in the atmosphere and thus would represent a more ancient form of energy production in cells.
Oxidative phosphorylation contributes the majority of the ATP produced, compared to glycolysis and the Krebs cycle. While the ATP count is glycolysis and the Krebs cycle is two ATP molecules, the electron transport chain contributes, at most, twenty-eight ATP molecules. A contributing factor is due to the energy potentials of NADH and FADH 2.
ADP and phosphate are needed as precursors to synthesize ATP in the payoff reactions of the TCA cycle and oxidative phosphorylation mechanism. [4] During the payoff phase of glycolysis, the enzymes phosphoglycerate kinase and pyruvate kinase facilitate the addition of a phosphate group to ADP by way of substrate-level phosphorylation. [5]
The overall process of creating energy in this fashion is termed oxidative phosphorylation. The same process takes place in the mitochondria, where ATP synthase is located in the inner mitochondrial membrane and the F 1-part projects into the mitochondrial matrix. By pumping proton cations into the matrix, the ATP-synthase converts ADP into ATP.
By controlling the amount of available reducing equivalents generated by the Krebs cycle, Oxoglutarate dehydrogenase has a downstream regulatory effect on oxidative phosphorylation and ATP production. [2] Reducing equivalents (such as NAD+/NADH) supply the electrons that run through the electron transport chain of oxidative phosphorylation ...
O-GlcNAcylation and phosphorylation can occur on the same threonine and serine residues, suggesting a complex relationship between these modifications that can affect many functions of the cell. [ 6 ] [ 12 ] The modification affects processes like the cells response to cellular stress, the cell cycle, protein stability and protein turnover.