Alpha-ketoglutarate dehydrogenase: a target and generator of oxidative stress

Philos Trans R Soc Lond B Biol Sci. 2005 Dec 29;360(1464):2335-45. doi: 10.1098/rstb.2005.1764.


Alpha-ketoglutarate dehydrogenase (alpha-KGDH) is a highly regulated enzyme, which could determine the metabolic flux through the Krebs cycle. It catalyses the conversion of alpha-ketoglutarate to succinyl-CoA and produces NADH directly providing electrons for the respiratory chain. alpha-KGDH is sensitive to reactive oxygen species (ROS) and inhibition of this enzyme could be critical in the metabolic deficiency induced by oxidative stress. Aconitase in the Krebs cycle is more vulnerable than alpha-KGDH to ROS but as long as alpha-KGDH is functional NADH generation in the Krebs cycle is maintained. NADH supply to the respiratory chain is limited only when alpha-KGDH is also inhibited by ROS. In addition being a key target, alpha-KGDH is able to generate ROS during its catalytic function, which is regulated by the NADH/NAD+ ratio. The pathological relevance of these two features of alpha-KGDH is discussed in this review, particularly in relation to neurodegeneration, as an impaired function of this enzyme has been found to be characteristic for several neurodegenerative diseases.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Citric Acid Cycle / physiology*
  • Humans
  • Ketoglutarate Dehydrogenase Complex / metabolism*
  • Ketoglutarate Dehydrogenase Complex / physiology
  • Mitochondria / metabolism*
  • NAD / metabolism*
  • Neurodegenerative Diseases / metabolism*
  • Oxidative Stress / physiology*
  • Reactive Oxygen Species / metabolism*


  • Reactive Oxygen Species
  • NAD
  • Ketoglutarate Dehydrogenase Complex