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Pyruvate, phosphate dikinase () is an enzyme in the family of transferases that catalyzes the chemical reaction :ATP + pyruvate + phosphate AMP + phosphoenolpyruvate + diphosphate This enzyme has been studied primarily in plants, but it has been studied in some bacteria as well. It is a key enzyme in gluconeogenesis and photosynthesis that is responsible for reversing the reaction performed by pyruvate kinase in Embden-Meyerhof-Parnas glycolysis. It should not be confused with pyruvate, water dikinase. It belongs to the family of transferases, to be specific, those transferring phosphorus-containing groups (phosphotransferases) with paired acceptors (dikinases). The systematic name of this enzyme class is ATP:pyruvate, phosphate phosphotransferase. Other names in common use include pyruvate, orthophosphate dikinase, pyruvate-phosphate dikinase (phosphorylating), pyruvate, phosphate dikinase, pyruvate-inorganic phosphate dikinase, pyruvate-phosphate dikinase, pyruvate-phosphate ligase, pyruvic-phosphate dikinase, pyruvic-phosphate ligase, pyruvate, Pi dikinase, and PPDK. This enzyme participates in pyruvate metabolism and carbon fixation. ==Reaction Mechanism== PPDK catalyses the conversion of pyruvate to phosphoenolpyruvate (PEP), consuming 1 molecule of ATP, and producing one molecule of AMP in the process. The mechanism consists of 3 reversible reactions: :1. The enzyme PPDK binds to ATP, to produce AMP and a disphosphorylated PPDK. :2. The disphosphorylated PPDK binds to inorganic phosphate, producing diphosphate and (mono)phosphorylated PPDK. :3. Phosphorylated PPDK binds to pyruvate, producing phosphoenolpyruvate, and regenerating PPDK. The reaction is similar to the reaction catalysed by pyruvate kinase, which also converts pyruvate to PEP. However, pyruvate kinase catalyses an irreversible reaction, and does not consume ATP. By contrast, PPDK catalyses a reversible reaction, and consumes 1 molecule of ATP for each molecule of pyruvate converted. Currently, the details of each mechanistic step is unknown〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「pyruvate phosphate dikinase」の詳細全文を読む スポンサード リンク
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