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Oxaloacetic acid (also known as oxalacetic acid or OAA) is a crystalline organic compound with the chemical formula HO 2 CC(O)CH 2 CO 2 H. Oxaloacetic acid, in the form of its conjugate base oxaloacetate, is a metabolic intermediate in many processes that occur in animals.
Oxaloacetate + 2 H + + 2 e − → Malate-0.17 [10] While under standard conditions malate cannot reduce the more electronegative NAD +:NADH couple, in the cell the concentration of oxaloacetate is kept low enough that Malate dehydrogenase can reduce NAD + to NADH during the citric acid cycle. Fumarate + 2 H + + 2 e − → Succinate +0.03 [9]
1. CO 2 is fixed to produce a four-carbon molecule (malate or aspartate). 2. The molecule exits the cell and enters the bundle sheath cells. 3. It is then broken down into CO 2 and pyruvate. CO 2 enters the Calvin cycle to produce carbohydrates. 4. Pyruvate reenters the mesophyll cell, where it is reused to produce malate or aspartate.
The reaction it catalyzes is: pyruvate + HCO − 3 + ATP → oxaloacetate + ADP + P. It is an important anaplerotic reaction that creates oxaloacetate from pyruvate. PC contains a biotin prosthetic group [1] and is typically localized to the mitochondria in eukaryotes with exceptions to some fungal species such as Aspergillus nidulans which have a cytosolic PC.
Malate, in the mitochondrial matrix, can be used to make pyruvate (catalyzed by malic enzyme) or oxaloacetic acid, both of which can enter the citric acid cycle. Glutamine can also be used to produce oxaloacetate during anaplerotic reactions in various cell types through "glutaminolysis", which is also seen in many c-Myc transformed cells. [ 3 ]
Plants that use the C 4 carbon fixation process chemically fix carbon dioxide in the cells of the mesophyll by adding it to the three-carbon molecule phosphoenolpyruvate (PEP), a reaction catalyzed by an enzyme called PEP carboxylase, creating the four-carbon organic acid oxaloacetic acid. Oxaloacetic acid or malate synthesized by this process ...
Oxaloacetate decarboxylase is a carboxy-lyase involved in the conversion of oxaloacetate into pyruvate.. It is categorized under EC 4.1.1.3.. Oxaloacetate decarboxylase activity in a given organism may be due to activity of malic enzyme, pyruvate kinase, malate dehydrogenase, pyruvate carboxylase and PEP carboxykinase or the activity of "real" oxaloacetate decarboxylases.
three ATP at a time for the NADH + H + produced within the α-ketoglutarate dehydrogenase reaction, the malate dehydrogenase reaction and the malate decarboxylase reaction. Due to low glutamate dehydrogenase and glutamate pyruvate transaminase activities, in tumor cells the conversion of glutamate to alpha-ketoglutarate mainly takes place via ...