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Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
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Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides

Published on: September 7, 2019

Methionine regulates copper/hydrogen peroxide oxidation products of Abeta

Feda E Ali1, Frances Separovic, Colin J Barrow

  • 1School of Chemistry, University of Melbourne, VIC 3010, Australia.

Journal of Peptide Science : an Official Publication of the European Peptide Society
|January 7, 2005
PubMed

Insights

Metal-catalysed oxidation (MCO) contributes to Alzheimer's disease (AD) pathogenesis. This study shows methionine influences MCO of amyloid beta peptide (Abeta), affecting oxidative stress in AD.

Area of Science:

  • Biochemistry
  • Neuroscience
  • Oxidative Stress Research

Background:

  • Metal-catalysed oxidation (MCO) is implicated in Alzheimer's disease (AD) pathogenesis.
  • Amyloid beta peptide (Abeta) interacts with copper ions, generating reactive oxygen species and free radicals via Fenton chemistry.
  • Abeta is susceptible to oxidative damage, particularly at methionine residues, influenced by metal ions and hydrogen peroxide.

Purpose of the Study:

  • To investigate the role of methionine in the metal-catalysed oxidation of Abeta.
  • To elucidate the mechanisms of oxidative stress in Alzheimer's disease.
  • To understand how methionine influences Abeta's susceptibility to MCO.

Main Methods:

  • Combined fluorescence assay and gel electrophoresis to monitor MCO of Abeta (1-28).
  • Investigated MCO in the presence and absence of methionine.
  • Utilized electrospray ionization mass spectrometry (ESI-MS) to analyze MCO products.

Main Results:

  • Methionine demonstrated a dual role: protecting some Abeta residues while promoting oxidation at Tyr(10).
  • ESI-MS identified methionine sulfoxide, methionine sulfone, and hydroxylated products from methionine MCO.
  • These oxidation products are similar to those formed from Met(35) of Abeta, suggesting potential alterations in peptide properties.

Conclusions:

  • Methionine significantly modulates the metal-catalysed oxidation of Abeta.
  • Oxidative modification of methionine residues in Abeta may alter its function and contribute to AD.
  • Further research into MCO of Abeta is crucial for understanding AD oxidative stress mechanisms.

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