What does acetylation mean?
Acetylation is the chemical process by which an acetyl group (CH₃CO–) is introduced into a molecule, usually replacing a hydrogen atom on an oxygen, nitrogen, or carbon atom. It is a fundamental reaction in both industrial and biological chemistry: in the laboratory, acetylation converts compounds such as salicylic acid into useful products like aspirin, while in living cells enzymes called acetyltransferases attach acetyl groups to proteins — most famously to histones, the spools around which DNA is wound. This biochemical form of acetylation can loosen or tighten DNA's packaging, switching genes on or off, making it central to the field of epigenetics. The reverse reaction, deacetylation, removes these groups. Because it underlies processes from drug manufacture to gene regulation, acetylation is a key concept in organic chemistry, molecular biology, and pharmacology alike.
nounThe chemical process of introducing an acetyl group (CH₃CO–) into a compound, typically by replacing a hydrogen atom, especially in organic chemistry and biochemistry.
- The addition of an acetyl group to a chemical compound, as in organic synthesis (e.g., producing aspirin from salicylic acid).
- In biochemistry, the enzymatic attachment of an acetyl group to proteins such as histones, a key mechanism regulating gene expression.
"The acetylation of histone proteins loosens the DNA coil, allowing genes to be read."
"Acetylation of cellulose yields cellulose acetate, used in photographic film."
"Researchers found that increased histone acetylation correlated with heightened gene activity."
Usually uncountable when referring to the process in general; plural forms appear mainly when discussing multiple specific instances or sites of modification.
"The mass spectrometry data revealed several distinct acetylations on the protein surface."
Tweak one tiny acetyl group on a histone protein and you can switch a human gene on or off — which is why acetylation sits at the heart of epigenetics.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of acetylation
Acetylation derives from 'acetyl', coined in the mid-19th century by the German chemist Justus von Liebig from Latin 'acetum' ('vinegar'), referring to the acetic acid radical. The suffix '-ation' forms nouns denoting a process, giving the word its sense of 'the act of adding an acetyl group'. Its cognates include acetic, acetate, and acetylene, all ultimately rooted in the same Latin word for vinegar.
Related word forms
How acetylation is actually used
A technical term confined to chemistry, biochemistry, and medicine; it is neutral in register but rarely encountered outside scientific writing. In biochemistry it often appears with a specifying modifier (e.g., 'histone acetylation', 'lysine acetylation').
Easily confused with acetylation
Deacetylation is the reverse process — the removal of an acetyl group from a molecule rather than its addition.