Acetyllysine (or acetylated lysine) is an

acetyl In organic chemistry, an acetyl group is a functional group denoted by the chemical formula and the structure . It is sometimes represented by the symbol Ac (not to be confused with the element actinium). In IUPAC nomenclature, an acetyl grou ...

-derivative of the

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. Lysine contains an α-amino group (which is in the protonated form when the lysine is dissolved in water at physiological pH), an α-carboxylic acid group ( ...

. There are multiple forms of acetyllysine: this article is about ''N''-ε-acetyl-L-lysine; another form is ''N''-α-acetyl-L-lysine. In

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

s, the

acetylation : In chemistry, acetylation is an organic esterification reaction with acetic acid. It introduces an acetyl group into a chemical compound. Such compounds are termed ''acetate esters'' or simply ''acetates''. Deacetylation is the opposite react ...

of lysine residues is an important mechanism of

epigenetics In biology, epigenetics is the study of changes in gene expression that happen without changes to the DNA sequence. The Greek prefix ''epi-'' (ἐπι- "over, outside of, around") in ''epigenetics'' implies features that are "on top of" or "in ...

. It functions by regulating the binding of

histone In biology, histones are highly basic proteins abundant in lysine and arginine residues that are found in eukaryotic cell nuclei and in most Archaeal phyla. They act as spools around which DNA winds to create structural units called nucleosomes ...

s to

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

nucleosome A nucleosome is the basic structural unit of DNA packaging in eukaryotes. The structure of a nucleosome consists of a segment of DNA wound around eight histone, histone proteins and resembles thread wrapped around a bobbin, spool. The nucleosome ...

s and thereby controlling the expression of genes on that DNA. Non-histone proteins are acetylated as well. Unlike the functionally similar

methyllysine Methyllysine is derivative of the amino acid residue lysine where the sidechain ammonium group has been methylated one or more times. Such methylated lysines play an important role in epigenetics; the methylation of specific lysines of certain hi ...

, acetyllysine does not carry a positive charge on its side chain.

Histone acetyltransferases Histone acetyltransferases (HATs) are enzymes that acetylate conserved lysine amino acids on histone proteins by transferring an acetyl group from acetyl-CoA to form ε-''N''-acetyllysine. DNA is wrapped around histones, and, by transferring an ...

(HATs) catalyze the addition of acetyl groups from

acetyl-CoA Acetyl-CoA (acetyl coenzyme A) is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidation, o ...

onto certain lysine residues of histones and non-histone proteins.

Histone deacetylases Histone deacetylases (, HDAC) are a class of enzymes that remove acetyl groups (O=C-CH3) from an ε-N-acetyl lysine amino acid on both histone and non-histone proteins. HDACs allow histones to wrap the DNA more tightly. This is important becaus ...

(HDACs) catalyze the removal of acetyl groups from acetylated lysines. Acetyllysine can be synthesized from lysine by the selective

of the terminal amine group.For example:

References

{{reflist Amino acid derivatives Alpha-Amino acids Acetamides