Acetyllysine

Acetyllysine refers to the lysine residue in which the epsilon amino group has been acetylated, typically described as Nε-acetyllysine. This modification is a common form of protein post-translational modification and can occur on histones and many non-histone proteins. The acetyl group is usually transferred from acetyl-CoA via lysine acetyltransferases and removed by deacetylases, including histone deacetylases and sirtuins.

Biochemical significance arises from the neutralization of the lysine positive charge, which can alter protein conformation, interactions, and stability. In chromatin biology, histone acetylation generally correlates with transcriptional activation because it reduces histone–DNA affinity and creates binding sites for bromodomain-containing proteins. Acetyllysine also modulates enzyme activity, signaling pathways, and protein–protein interactions beyond chromatin-related processes.

In research and analysis, acetyllysine is often studied as a post-translational modification marker. Detection methods include antibodies specific for acetyllysine and mass spectrometry-based proteomics to identify and quantify acetylation sites. Synthetic peptides or proteins containing Nε-acetyllysine serve as standards or substrates to characterize acetyltransferase and deacetylase activities.

Applications extend to epigenetics, cell signaling, and proteomics, where acetylation state serves as a regulatory readout or functional modifier. While acetyllysine is endogenous in many proteins, it is also used in experimental systems to investigate the effects of lysine acetylation on structure and function.