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4-Oxo-2-nonenal is both more neurotoxic and more protein reactive than 4-hydroxy-2-nonenal

De Lin1, Hyoung-gon Lee, Quan Liu

  • 1Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA.

Chemical Research in Toxicology
|August 16, 2005
PubMed

Insights

Oxidative stress generates electrophilic aldehydes like 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE), which are toxic to neuroblastoma cells. ONE exhibits higher neurotoxicity and reactivity with proteins compared to HNE.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Toxicology

Background:

  • Electrophilic aldehydes, products of polyunsaturated fatty acid oxidation during oxidative stress, can damage proteins and DNA, leading to cell death.
  • 4-Hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) are key aldehydes implicated in cellular damage.

Purpose of the Study:

  • To compare the neurotoxicity and protein reactivity of HNE and ONE.
  • To elucidate the reaction mechanisms of HNE and ONE with proteins and amino acids.

Main Methods:

  • Spectrophotometric analysis of aldehyde-protein reactions.
  • Kinetic studies of aldehyde reactions with amino acids and model proteins.
  • Neuroblastoma cell culture and toxicity assays.

Main Results:

  • ONE is 4-5 times more neurotoxic than HNE to human neuroblastoma cells.
  • ONE reacts 6-31 times faster with model proteins (ribonuclease A, beta-lactoglobulin) than HNE.
  • ONE primarily forms Schiff bases with lysine residues, while HNE shows less apparent Schiff base formation.
  • Kinetic analyses revealed reversible Michael adduct formation for HNE with amines and Schiff base adduct formation for ONE with amines.

Conclusions:

  • ONE's greater neurotoxicity may stem from its distinct reactivity profile compared to HNE.
  • Differential reactivity of HNE and ONE with nucleophiles (amines, imidazoles, thiols) influences their biological effects.

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