Formation and biological value of acetyl-CoA
The introduction of an acetyl group into a molecule is called acetylation. In biological organisms, acetyl groups are commonly transferred from acetyl-CoA to coenzyme A (CoA). Acetyl-CoA is an intermediate both in the biological synthesis and in the breakdown of many organic molecules. Acetyl-CoA is also created during the second stage of cellular respiration, the Kreb's Cycle. It is formed from pyruvic acid with the help of water and is later bonded to a pre-existing four-carbon molecule to carry out the Kreb's Cycle.
Histones and other proteins are often modified by acetylation. For example, on the DNA level, histone acetylation by acetyltransferases (HATs) causes an expansion of chromatin architecture, allowing for genetic transcription to occur. However, removal of the acetyl group by histone deacetylases (HDACs) condenses DNA structure, thereby preventing transcription.[3] In addition to HDACs, Methyl group additions are able to bind DNA resulting in DNA methylation, and this is another common way to block DNA acetylation and inhibit gene transcription.
Synthetic organic and pharmaceutical chemistry[edit]
Acetylation can be achieved using a variety of methods, the most common one being via the use of acetic anhydride or acetyl chloride, often in the presence of a tertiary or aromatic amine base. A typical acetylation is the conversion of glycine to N -acetylglycine:[4]
H2NCH2CO2H + (CH3CO)2O → CH3C(O)NHCH2CO2H + CH3CO2H
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