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Beta-elimination: an unexpected artefact in proteome analysis.
Ben Herbert1, Femia Hopwood, David Oxley
1Proteome Systems, North Ryde, Sydney, NSW, Australia. ben.herbert@proteosystems.com
Proteomics
|July 2, 2003
Summary
A novel artifact, beta-elimination, causes protein degradation during proteome analysis by removing sulfur from cysteine residues. Pre-treatment with reduction and alkylation prevents this degradation.
Area of Science:
- Proteomics
- Biochemistry
- Analytical Chemistry
Background:
- Established electrophoretic literature contains persistent myths like carbamylation and deamidation.
- These myths have been recently debunked, necessitating a re-evaluation of analytical artifacts.
Purpose of the Study:
- To report a newly identified, unexpected artifact in proteome analysis.
- To investigate the mechanism and consequences of beta-elimination in protein analysis.
Main Methods:
- Proteome analysis focusing on protein separation in the alkaline pH region.
- Investigation of degradation pathways affecting cysteine residues.
Main Results:
- Beta-elimination (desulfuration) was identified as a significant artifact, causing loss of H(2)S from cysteine residues.
- This process generates dehydroalanine, leading to peptide bond lysis and fragmentation of intact proteins.
- The electric field appears to promote beta-elimination by harvesting SH(-) anions.
Conclusions:
- Reduction and alkylation of cysteine residues prior to electrophoresis is a crucial remedy.
- This pre-treatment effectively prevents beta-elimination and subsequent peptide bond lysis, preserving protein integrity.