Molecular Classification
Enzyme
Other Names
Krebs Cycle Enzymes, Tricarboxylic Acid Cycle Enzymes
Disease Roles
Metabolic DisordersCancer (indirectly through metabolic alterations)Mitochondrial Diseases

Citric Acid Cycle Enzymes Overview

The citric acid cycle (also known as the Krebs cycle or tricarboxylic acid [TCA] cycle) is a central metabolic pathway that takes place in the mitochondrial matrix of eukaryotic cells. It is responsible for the oxidative catabolism of carbohydrates, fats, and proteins, converting acetyl-CoA into carbon dioxide while generating high-energy electron carriers (NADH and FADH2) and GTP/ATP. The enzymes catalyzing this cycle are essential for cellular respiration and energy production. The main enzymes involved are: Citrate synthase, Aconitase, Isocitrate dehydrogenase, α-Ketoglutarate dehydrogenase complex, Succinyl-CoA synthetase, Succinate dehydrogenase, Fumarase, and Malate dehydrogenase. Defects in these enzymes can lead to metabolic disorders affecting energy production. Some intermediates/enzyme activities are also targets for certain drugs or toxins.

Mechanism of Action

Enzyme Inhibition

Biological Functions

Cellular Respiration
Energy Production
Metabolism of Carbohydrates, Fats, and Proteins
Redox Reactions
Biosynthesis Precursor Generation

Disease Associations

Metabolic Disorders
Cancer (indirectly through metabolic alterations)
Mitochondrial Diseases

Safety Considerations

  • Disruption of cellular energy production
  • Accumulation of toxic metabolites
  • Potential for drug interactions due to metabolic pathway involvement

Interacting Drugs

Fluoroacetate (aconitase inhibitor)
Arsenite (alpha-ketoglutarate dehydrogenase inhibitor)

Associated Biomarkers

Biomarker
Levels of citric acid cycle intermediates (e.g., citrate, succinate, fumarate)