Detailed Explanation
Acetylation is one of the most common post-translational modifications in biology. When an acetyl group is added to the N-terminus of a peptide (N-terminal acetylation), it protects the peptide from degradation by aminopeptidases — enzymes that normally chew up unprotected peptide chains. This is why roughly 80–90% of human proteins are N-terminally acetylated.
Lysine acetylation, on the other hand, is a reversible regulatory switch. Histone acetylation by acetyltransferase enzymes opens up chromatin structure and activates gene transcription. Deacetylases (HDACs and sirtuins) reverse the process. This acetylation/deacetylation balance is central to gene regulation, aging research, and cancer biology.
In peptide drug design, N-terminal acetylation is frequently used to improve metabolic stability. An acetylated peptide resists aminopeptidase degradation, extending its useful half-life in the body.
Key Facts
- ~80–90% of human proteins are N-terminally acetylated
- Protects peptides from aminopeptidase degradation
- Histone acetylation regulates gene expression
- Reversible: added by acetyltransferases, removed by deacetylases (HDACs)
- Widely used in peptide drug design to extend half-life
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