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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.
Firstly the oxaloacetate is reduced to malate using NADH. Then the malate is decarboxylated to pyruvate. Now this pyruvate can easily enter the mitochondria, where it is carboxylated again to oxaloacetate by pyruvate carboxylase. In this way, the transfer of acetyl-CoA that is from the mitochondria into the cytoplasm produces a molecule of NADH.
Pyruvate, the conjugate base, CH 3 COCOO −, is an intermediate in several metabolic pathways throughout the cell. Pyruvic acid can be made from glucose through glycolysis , converted back to carbohydrates (such as glucose) via gluconeogenesis , or converted to fatty acids through a reaction with acetyl-CoA . [ 3 ]
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.
Pyruvate generated from alanine will enter glyceroneogenesis and generate glycerol 3-phosphate. Glutamate can also enter glyceroneogenesis. Since the key reaction of glyceroneogenesis is the decarboxylation and phosphorylation of oxaloacetate to phosphoenolpyruvate, in theory any biochemical pathway which generates oxaloacetate is related to ...
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]
Pyruvate molecules produced by glycolysis are actively transported across the inner mitochondrial membrane, and into the matrix where they can either be oxidized and combined with coenzyme A to form CO 2, acetyl-CoA, and NADH, [35] or they can be carboxylated (by pyruvate carboxylase) to form oxaloacetate.
Gluconeogenesis begins in the mitochondria with the formation of oxaloacetate by the carboxylation of pyruvate. This reaction also requires one molecule of ATP, and is catalyzed by pyruvate carboxylase. This enzyme is stimulated by high levels of acetyl-CoA (produced in β-oxidation in the liver) and inhibited by high levels of ADP and glucose.