The Acetyl Group – Definition and Structure
In this reading, you will learn all about the acetyl group, including what it is, its specific structure, and some of the common molecules that contain it. Have you ever traveled to a foreign country? Have you heard of ordering your food in a new language? Or, asking where the bathroom is? If you have, and if you did not speak that language well, you might have gotten blank looks in response. It is in those moments that you understand how important language is to everything you do in life. Organic chemistry is much the same. If you don’t understand the language, you might not get very far. Sometimes you need a science dictionary to help remind you what all of the new terms mean!
In organic chemistry, acetyl (ethanol) is a functional group, the acyl of acetic acid, by the chemical formula -COCH3. It is seldom abbreviated as Ac (not to be confused with the element actinium). The acetyl radical carries a methyl group single-bonded to a carbonyl. The carbonyl carbon has a solitary electron available, with which it forms a chemical bond to the remains R of the molecule. The acetyl radical is a part of many organic compounds, including the neurotransmitter acetylcholine and acetyl-CoA, and the analgesics acetaminophen and acetylsalicylic acid (better recognized as aspirin).
The Acetyl Group
An acetyl group is, front and foremost, a moiety. A moiety is only a part of a molecule. So, an acetyl group is a part of a molecule and is not a unit unto itself. Thus, an arm or a leg is a part of a body but could not stand on its own to be its personal body.
Secondly, an acetyl group is a member of a larger family of moieties called an acyl group. An acyl group is built up of two parts. First is the carbonyl group. A carbonyl group is a carbon dual bonded to oxygen. A second component is an alkyl group, which is solely a moiety made up of carbons and hydrogens.
The Acetyl Group Structure
Just like the acyl group, the acetyl group is created up of two parts. Like the acyl, the first part is a carbonyl group made up of a carbon double bonded to oxygen. The second part, however, is more specific. Since the acetyl group is a type of acyl groups, we recognize that this second component must be an alkyl group, but it is more specific. In this case, it is a methyl group, which is simply a carbon with three hydrogens (CH3).
The debut of an acetyl group into a molecule is called acetylation (or ethanoylation). In biological organisms, acetyl groups are usually transferred bound to Coenzyme A (CoA), in the form of acetyl-CoA. Acetyl-CoA is an essential intermediate both in the biological synthesis and in the breakdown of many organic molecules.
Acetyl groups are also often added to histones and other proteins, modifying their properties. For example, histone acetylation by histone acetyltransferases (HATs) causes an expansion of chromatin architecture on the DNA level, allowing for genetic transcription to occur.
Conversely, replacement of the acetyl group by histone deacetylases (HDACs) condenses DNA structure, thereby preventing transcription. Chemical acetylation can be done using various methods, most commonly by the use of acetic anhydride or acetyl chloride in the presence of a tertiary or aromatic amine base.
This paper addresses a robust method to quantify the acetyl group in biomass and its derived liquid or solid samples using headspace gas chromatography (HS–GC). The method was based on the sample pre-treatment in an oxalic acid medium (0.6 mol/L) at 150 °C and 10 min for the liquid units or 70 min for the concrete examples to convert the acetyl group to acetic acid, which can be quantified by a full evaporation HS–GC technique. It was found that ∼100 μm was the suitable substantial particle size used in the sample analysis at the suggested pre-treatment condition.
The outcomes showed that the present method has good measurement precision (relative standard deviation was less than 2.09% for the liquid sample and 2.83% for the solid sample) and correctness (with the returns of 96.2–104% in the acetyl group quantification). The boundary of quantification of the method was 163 mg/L for the biomass liquid samples and 0.11% for the solid biomass samples. The existing process can be a valuable tool to provide high-throughput testing for the acetyl group in biomass and its derived units in bio refinery-related development.
So this was a complete guide, where you learn all about the acetyl group, including what it is, its specific structure, and some of the common molecules that contain it. Share your valuable and precious thoughts in the comment box section below.