PURPOSE: Amyloid-beta (Abeta) is a self-aggregating protein found in senile plaques in Alzheimer's disease (AD) brain and is thought to play a major role in the disease process. Oxidative stress may be a predominant cause of the formation of these Abeta aggregates. This study aims at identifying possible sites of copper-catalyzed oxidation of Abeta1-40 using liquid chromatography tandem mass spectrometry (LC/MS/MS) and scoring algorithm for spectral analysis (SALSA). Traditionally, identification of post-translational modifications by tandem mass spectrometric analysis requires users to inspect manually thousands of MS/MS spectra, which can be a tedious and time-consuming process. With the use of SALSA, users can automatically search for post-translational modifications based on the spacing of the m/z values associated with the ion series of an amino acid sequence. METHODS: Abeta1-40 was subjected to copper-catalyzed oxidative stress. LC/MS/MS and SALSA analyses were used to determine the sites of post-translational modification within the tryptic fragments. RESULTS: Oxidation was found to occur preferentially at the histidine residues Hisl3 and Hisl4 and at the methionine residue (Met35) of Abeta1-40. CONCLUSIONS: The combination of LC/MS/MS and SALSA searches could dramatically improve the efficiency and accuracy of determining the specific sites of oxidation of in vitro, copper-oxidized Abeta1-40 as well as other oxidized proteins.
PURPOSE: Amyloid-beta (Abeta) is a self-aggregating protein found in senile plaques in Alzheimer's disease (AD) brain and is thought to play a major role in the disease process. Oxidative stress may be a predominant cause of the formation of these Abeta aggregates. This study aims at identifying possible sites of copper-catalyzed oxidation of Abeta1-40 using liquid chromatography tandem mass spectrometry (LC/MS/MS) and scoring algorithm for spectral analysis (SALSA). Traditionally, identification of post-translational modifications by tandem mass spectrometric analysis requires users to inspect manually thousands of MS/MS spectra, which can be a tedious and time-consuming process. With the use of SALSA, users can automatically search for post-translational modifications based on the spacing of the m/z values associated with the ion series of an amino acid sequence. METHODS: Abeta1-40 was subjected to copper-catalyzed oxidative stress. LC/MS/MS and SALSA analyses were used to determine the sites of post-translational modification within the tryptic fragments. RESULTS: Oxidation was found to occur preferentially at the histidine residues Hisl3 and Hisl4 and at the methionine residue (Met35) of Abeta1-40. CONCLUSIONS: The combination of LC/MS/MS and SALSA searches could dramatically improve the efficiency and accuracy of determining the specific sites of oxidation of in vitro, copper-oxidized Abeta1-40 as well as other oxidized proteins.
Authors: D T Dexter; C J Carter; F R Wells; F Javoy-Agid; Y Agid; A Lees; P Jenner; C D Marsden Journal: J Neurochem Date: 1989-02 Impact factor: 5.372
Authors: X Huang; M P Cuajungco; C S Atwood; M A Hartshorn; J D Tyndall; G R Hanson; K C Stokes; M Leopold; G Multhaup; L E Goldstein; R C Scarpa; A J Saunders; J Lim; R D Moir; C Glabe; E F Bowden; C L Masters; D P Fairlie; R E Tanzi; A I Bush Journal: J Biol Chem Date: 1999-12-24 Impact factor: 5.157