Selective N-terminal functionalization of native peptides and proteins

Area of Science:

• Biochemistry
• Organic Chemistry
• Chemical Biology

Background:

• Selective modification of peptides and proteins is crucial for various applications.
• Existing methods often lack N-terminal specificity or require harsh conditions.

Purpose of the Study:

• To develop an efficient and highly selective method for N-terminal amine modification in peptides and proteins.
• To demonstrate the utility of this method for introducing bioorthogonal functional groups and preserving bioactivity.

Main Methods:

• Reductive alkylation using aldehyde derivatives.
• Modification of a peptide library with benzaldehyde.
• Testing the method on native peptides and proteins, including human insulin.

Main Results:

• Achieved excellent N-terminal selectivity (>99:1 α-amino/ε-amino) with high conversion for most peptides.
• Demonstrated selective modification of native peptides and proteins with various aldehydes.
• Showed a 5-fold increase in human insulin bioactivity by preserving N-terminal positive charge via reductive alkylation.

Conclusions:

• The reported reductive alkylation method provides a universal strategy for site-selective N-terminal functionalization.
• This method is efficient, highly selective, and preserves or enhances protein bioactivity.