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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.
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.
This reaction is catalysed by pyruvate carboxylase, an enzyme activated by acetyl-CoA, indicating a lack of oxaloacetate. It occurs in animal mitochondria. Most important anaplerotic reaction; depending on severity, deficiency causes lactic acidosis, severe psychomotor deficiency or death in infancy
This reaction requires inorganic phosphate and ATP plus pyruvate, producing PEP, AMP, and inorganic pyrophosphate (PP i). The next step is the carboxylation of PEP by the PEP carboxylase enzyme (PEPC) producing oxaloacetate. Both of these steps occur in the mesophyll cells: pyruvate + P i + ATP → PEP + AMP + PP i PEP + CO 2 → oxaloacetate
However, it is also possible for pyruvate to be carboxylated by pyruvate carboxylase to form oxaloacetate. This latter reaction "fills up" the amount of oxaloacetate in the citric acid cycle, and is therefore an anaplerotic reaction, increasing the cycle's capacity to metabolize acetyl-CoA when the tissue's energy needs (e.g. in muscle) are ...
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.
This enzyme belongs to the family of oxidoreductases, to be specific those acting on the CH-OH group of donor with NAD + or NADP + as acceptor. The systematic name of this enzyme class is (S)-malate:NADP + oxidoreductase (oxaloacetate-decarboxylating). This enzyme participates in pyruvate metabolism and carbon fixation.
The others are NADP-malic enzyme and NAD-malic enzyme. [17] [18] In C 4 carbon fixation, carbon dioxide is first fixed by combination with phosphoenolpyruvate to form oxaloacetate in the mesophyll. In PEPCK-type C 4 plants the oxaloacetate is then converted to aspartate, which travels to the bundle sheath.