Beta-amyloid inhibits integrated mitochondrial respiration and key enzyme activities

J Neurochem. 2002 Jan;80(1):91-100. doi: 10.1046/j.0022-3042.2001.00681.x.


Disrupted energy metabolism, in particular reduced activity of cytochrome oxidase (EC, alpha-ketoglutarate dehydrogenase (EC and pyruvate dehydrogenase (EC have been reported in post-mortem Alzheimer's disease brain. beta-Amyloid is strongly implicated in Alzheimer's pathology and can be formed intracellularly in neurones. We have investigated the possibility that beta-amyloid itself disrupts mitochondrial function. Isolated rat brain mitochondria have been incubated with the beta-amyloid alone or together with nitric oxide, which is known to be elevated in Alzheimer's brain. Mitochondrial respiration, electron transport chain complex activities, alpha-ketoglutarate dehydrogenase activity and pyruvate dehydrogenase activity have been measured. Beta-amyloid caused a significant reduction in state 3 and state 4 mitochondrial respiration that was further diminished by the addition of nitric oxide. Cytochrome oxidase, alpha-ketoglutarate dehydrogenase and pyruvate dehydrogenase activities were inhibited by beta-amyloid. The K(m) of cytochrome oxidase for reduced cytochrome c was raised by beta-amyloid. We conclude that beta-amyloid can directly disrupt mitochondrial function, inhibits key enzymes and may contribute to the deficiency of energy metabolism seen in Alzheimer's disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid beta-Peptides / pharmacology*
  • Animals
  • Brain / enzymology
  • Brain / metabolism*
  • Drug Combinations
  • Electron Transport / drug effects
  • Enzymes / metabolism*
  • Male
  • Mitochondria / enzymology
  • Mitochondria / metabolism*
  • Nitric Oxide / pharmacology
  • Oxygen Consumption / drug effects*
  • Rats
  • Rats, Wistar


  • Amyloid beta-Peptides
  • Drug Combinations
  • Enzymes
  • Nitric Oxide