Acetyltransferase

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Choline acetyltransferase (ChAT or CAT, EC  2.3.1.6 )
Acetyl-CoA-acetyltransferase complex ( EC  2.3.1.9 )

Acetyltransferases are enzymes that transfer an acetic acid residue ( acetyl residue ) to suitable acceptors. These enzymes are transferases ( EC  2.3.-.- ) and belong to the acyl transferases ( EC  2.3.1.- ), because they transfer the acetyl residue from a donor to an acceptor. The replacement of a certain hydrogen atom of the acceptor by an acetyl radical is called acetylation .

Many acetylations affect proteins as acceptors and take place in the context of regulatory processes, e.g. B. the acetylation of histones as part of the histone modification , often with epigenetic effects, or the Tat protein (transactivator of transcription protein) of the HI virus to regulate its activity. Often a lysyl residue of the protein is acetylated, in the case of histones and Tat protein only.

Acetyl-coenzyme A usually serves as a donor for the acetyl group and for the acetylation energy . This coenzyme A is acetylated by acetyl-CoA-acetyltransferase (ACAT), also an acetyltransferase ( EC  2.3.1.9 ).

Transfer of an acetyl group to serotonin by serotonin-N-acetyltransferase (aralkylamine N-acetyltransferase, AANAT, EC  2.3.1.87 )

Acetyl transferases are often referred to as acetylases . This is confusing, because acetyl transferase reactions have to be distinguished from other enzymatic changes that result in an acetyl group without its atoms being transferred from a donor to the acceptor. Some enzymes of the enzyme groups EC  2.8.2.- , EC  3.1.1.- , EC  3.1.2.- , EC  3.4.13.- and EC  3.5.1.- are also referred to synonymously as acetylases or deacetylases.

The opposite reaction, the removal of an acetyl group, is caused by deacetylases, also not a single enzyme group. Deacetylation of proteins often achieves a regulatory effect that counteracts acetylation.

Examples of acetyltransferases

Individual evidence

  1. ↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 1: A-Cl. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1979, ISBN 3-440-04511-0 , p. 47.
  2. ↑ Wilma Dormeyer: The biochemical analysis of protein acetylation using the example of the HIV-1 Tat protein . Dissertation, 2003, Ruhr University Bochum (PDF; 2.2 MB)
  3. ↑ Query of the BRENDA enzyme database with "acetylase" on February 6, 2013 yielded 202 results, including 26 synonyms for acetyltransferases