Standard Article

Citric Acid Cycle

  1. Kathryn F LaNoue

Published Online: 19 APR 2001

DOI: 10.1038/npg.els.0001369



How to Cite

LaNoue, K. F. 2001. Citric Acid Cycle. eLS. .

Author Information

  1. Pennsylvania State University, Hershey, Pennsylvania, USA

Publication History

  1. Published Online: 19 APR 2001


The citric acid cycle is a metabolic pathway common to aerobic cells by which carbohydrates, fats and amino acids are oxidized to carbon dioxide and water. Enzymes catalyse the condensation of two- and four-carbon compounds to citric acid, and then enzymatic oxidations and decarboxylations regenerate the four-carbon starting compound plus CO2 and H2O. The energy available from the downhill flow of electrons to oxygen is used indirectly for the synthesis of ATP, the energy currency of the cell.


  • respiration;
  • adenosine triphosphate;
  • áketoglutarate;
  • citrate synthase