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Sample Preparation and Relative Quantitation using Reductive Methylation of Amines for Peptidomics Studies
Published on: November 4, 2021
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Evaluation and optimization of reduction and alkylation methods to maximize peptide identification with MS-based
Suttipong Suttapitugsakul1, Haopeng Xiao, Johanna Smeekens
1School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA. ronghu.wu@chemistry.gatech.edu.
Molecular Biosystems
|October 12, 2017
Summary
Optimizing reduction and alkylation is key for mass spectrometry proteomics. Iodoacetamide proved most effective for cysteine alkylation, significantly improving peptide identification and reducing side reactions in bottom-up proteomics.
Area of Science:
- Proteomics
- Analytical Chemistry
- Biochemistry
Background:
- Mass spectrometry (MS)-based proteomics is vital for protein analysis.
- Routine reduction and alkylation steps in bottom-up proteomics can suffer from incomplete or side reactions, impacting data quality.
Purpose of the Study:
- To systematically evaluate common reduction and alkylation reagents for bottom-up MS proteomics.
- To optimize conditions for improved peptide identification, particularly for cysteine-containing peptides.
Main Methods:
- Comparative analysis of four reducing agents (dithiothreitol, 2-mercaptoethanol, tris(2-carboxyethyl)phosphine, tris(3-hydroxypropyl)phosphine) and four alkylating agents (iodoacetamide, acrylamide, N-ethylmaleimide, 4-vinylpyridine).
- Optimization of iodoacetamide alkylation conditions.
- Enrichment of cysteine-containing peptides using thiopropyl-sepharose 6B resins.
Main Results:
- Reducing agents showed similar performance in peptide identification.
- Iodoacetamide yielded the highest number of alkylated cysteines and fewest side reactions compared to other alkylating agents.
- Optimization and enrichment strategies increased the identification of cysteine-containing peptides over threefold.
Conclusions:
- Systematic evaluation of reagents is crucial for optimizing bottom-up proteomic experiments.
- Iodoacetamide is a superior alkylating agent for cysteine modification in MS proteomics.
- Peptide enrichment significantly enhances the detection of cysteine-modified peptides.
