Oxidation
Oxidation — A chemical reaction involving electron loss, commonly affecting methionine and cysteine residues in peptides and leading to reduced activity and purity.
What Is Oxidation?
Oxidation is the most common chemical degradation pathway for peptides, primarily affecting methionine (to sulfoxide, +16 Da), tryptophan (to kynurenine, N-formylkynurenine), histidine (to 2-oxo-His), and cysteine (to sulfenic/sulfinic acid). Oxidation reduces bioactivity, alters receptor binding, and increases immunogenicity.
Prevention Strategies
- Nitrogen overlay: Replace headspace oxygen with nitrogen or argon during lyophilization and storage
- Antioxidants: Free Met (0.1-1 mM) as sacrificial scavenger. EDTA chelates metal catalysts
- Light protection: Amber vials or foil overwrap for photosensitive peptides
- pH control: Metal-catalyzed oxidation accelerates at alkaline pH
Frequently Asked Questions
What is Oxidation?
A chemical reaction involving electron loss, commonly affecting methionine and cysteine residues in peptides and leading to reduced activity and purity.
Why is Oxidation important in peptide research?
Oxidation is a fundamental concept in degradation as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.