Deamidation
Deamidation — A chemical degradation reaction where asparagine or glutamine residues lose an amide group, a common concern in peptide stability and storage.
What Is Deamidation?
Deamidation is the conversion of asparagine (Asn) to aspartate (Asp) and isoaspartate (isoAsp) through a succinimide intermediate, with a +1 Da mass shift. It is the most predictable chemical degradation in peptides because the rate depends primarily on the residue following Asn: Asn-Gly is fastest (t1/2 ~1 day at 37°C, pH 7.4), while Asn-Pro is extremely slow.
Impact and Control
- Charge change: Neutral Asn becomes negatively charged Asp, altering pI and potentially receptor binding
- Detection: +1 Da on MS, additional peaks on HPLC, charge shift on IEX
- Prevention: Formulate at pH 4-5, minimize temperature, lyophilize to reduce water activity
- Design: Avoid Asn-Gly and Asn-Ser in synthetic peptide sequences when possible
Frequently Asked Questions
What is Deamidation?
A chemical degradation reaction where asparagine or glutamine residues lose an amide group, a common concern in peptide stability and storage.
Why is Deamidation important in peptide research?
Deamidation 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.