Anaplerotic reactions

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Anaplerotic ( ancient Greek ἀνά – πληρόω fill up, make complete ) reactions are metabolic pathways that supply the citric acid cycle . They compensate for losses of intermediates of the citric acid cycle, caused by branching off these intermediates for biosynthesis . In contrast, there are cataplerotic reactions.

An example of an anaplerotic reaction is the synthesis of oxaloacetate from pyruvate and carbon dioxide , catalyzed by pyruvate carboxylase :

Pyruvate + CO 2 + ATP + H 2 O → oxaloacetate + ADP + P i + 2 H +

The energy required for the reaction is provided by the hydrolysis of ATP to ADP and phosphate.

This replenishment reaction is necessary in mammals because they do not have the enzyme to convert acetyl-CoA to oxaloacetate or any other intermediate. Other anaplerotic metabolic pathways belong to the amino acid metabolism. B. aspartate or glutamate converted by oxidative deamination to the intermediates oxaloacetate or α-ketoglutarate .


  • Albert L. Lehninger: Principles of Biochemistry . de Gruyter, Berlin, New York 1987, ISBN 3-11-008988-2 , pp. 501-502.
  • Lubert Stryer: Biochemistry . 4th edition, Spektrum, Heidelberg 1990, ISBN 3-89330-690-0 , pp. 403-404.