Glossary
Acetylation
N-terminal acetylation blocks a peptide’s free amine, adds 42.01 Da and shields it from aminopeptidases. How it shows up on a COA and which vials carry it.
Acetylation places an acetyl group (CH3CO–) on a free amine of a peptide. The usual site is the N-terminus: the cap raises the molecular mass by 42.01 Da and eliminates the positive charge at that end. Lysine side chains can be acetylated too. In product names you will see it as an "N-Acetyl" or "Acetyl" prefix.
Effects of the acetyl cap
Aminopeptidases need an unblocked N-terminal amine to start digesting a chain. Capping it takes away that entry point, so acetylated analogs usually last longer than their parent sequence in plasma or tissue-homogenate stability experiments. The cap also adds hydrophobic character at the N-terminus, nudging retention time upward on reverse-phase HPLC — a handy way to confirm the modification is really there.
Acetylated items in our range
N-Acetyl Semax Amidate and N-Acetyl Selank Amidate pair the acetyl cap with C-terminal amidation, so both ends of the backbone are blocked. Among cosmetic research peptides, Argireline (acetyl hexapeptide-8) and SNAP-8 are acetylated as well.
What this means for your data
An acetyl group is more than a naming detail. It shifts the expected mass that a mass-spec result has to hit, alters how the compound behaves on a column, and makes the capped and uncapped forms of one sequence separate research materials — they should never be swapped for one another.
Related terms
peptide bond · degradation · analog.