acetylation

Histone deacetylases "play crucial roles in gene transcription and most likely in all eukaryotic biological processes that involve chromatin".

Acetylation is one type of post-translational modification of proteins. The acetylation of the ε-amino group of lysine, which is common, converts a charged side chain to a neutral one.{{cite journal|doi=10.1021/acs.chemrev.7b00181|title=Lysine Acetylation Goes Global: From Epigenetics to Metabolism and Therapeutics|year=2018|last1=Ali|first1=Ibraheem|last2=Conrad|first2=Ryan J.|last3=Verdin|first3=Eric|last4=Ott|first4=Melanie|journal=Chemical Reviews|volume=118|issue=3|pages=1216–1252|pmid=29405707|pmc=6609103}} Acetylation/deacetylation of histones also plays a role in gene expression and cancer.{{cite journal |doi=10.1038/nrd2133|title=Anticancer activities of histone deacetylase inhibitors|year=2006|last1=Bolden|first1=Jessica E.|last2=Peart|first2=Melissa J.|last3=Johnstone|first3=Ricky W.|journal=Nature Reviews Drug Discovery|volume=5|issue=9|pages=769–784|pmid=16955068|s2cid=2857250}} These modifications are effected by enzymes called histone acetyltransferases (HATs) and histone deacetylases (HDACs).{{cite journal |doi=10.1146/annurev.biochem.76.052705.162114|title=Functions of Site-Specific Histone Acetylation and Deacetylation|year=2007|last1=Shahbazian|first1=Mona D.|last2=Grunstein|first2=Michael|journal=Annual Review of Biochemistry|volume=76|pages=75–100|pmid=17362198}}

Two general mechanisms are known for deacetylation. One mechanism involves zinc binding to the acetyl oxygen. Another family of deacetylases require NAD⁺, which transfers an ribosyl group to the acetyl oxygen.{{cite journal |doi=10.1101/cshperspect.a018713|title=Erasers of Histone Acetylation: The Histone Deacetylase Enzymes |year=2014 |last1=Seto |first1=E. |last2=Yoshida |first2=M. |journal=Cold Spring Harbor Perspectives in Biology |volume=6 |issue=4 |pages=a018713 |pmid=24691964 |pmc=3970420 }}

Acetate esters{{cite journal |doi=10.15227/orgsyn.004.0001|title=Acetylmandelic Acid and Acetylmandelyl Chloride|journal=Organic Syntheses|year=1925|volume=4|page=1|author=F. K. Thayer}} and acetamides{{cite journal |doi=10.15227/orgsyn.019.0004|title=Acetylglycine|journal=Organic Syntheses|year=1939|volume=19|page=4|first1=R. M. |last1=Herbst |first2=D. |last2=Shemin}} are generally prepared by acetylations. Acetylations are often used in making C-acetyl bonds in Friedel-Crafts reactions.{{cite journal |doi=10.15227/orgsyn.028.0003|title=2-Acetylfluorene|journal=Organic Syntheses|year=1948|volume=28|page=3|author=F. E. Ray and George Rieveschl, Jr}}{{cite journal |doi=10.15227/orgsyn.030.0001|title=9-Acetylanthracene|journal=Organic Syntheses|year=1950|volume=30|page=1|first1=Charles|last1=Merritt, Jr.|first2=Charles E.|last2=Braun

}} Carbanions and their equivalents are susceptible to acetylations.{{OrgSynth | title = Acetylacetone | first1 = C. E. Jr. |last1 =Denoon | first2 =Homer| last2 =Adkins| first3 =James L.| last3 =Rainey | volume = 20 | page = 6 | doi = 10.15227/orgsyn.020.0006|year=1940}}

Many acetylations are achieved using these three reagents:

• Acetic anhydride. This reagent is common in the laboratory; its use cogenerates acetic acid.{{cite journal | last=Mantanis | first=George I. | author-link=George Mantanis | title= Chemical modification of wood by acetylation or furfurylation: A review of the present scaled-up technologies | journal=BioResources | volume=12 | issue=2 | date=2017 | doi= 10.15376/biores.12.2.Mantanis | pages=4478-4489| doi-access=free }}
• Acetyl chloride. This reagent is also common in the laboratory, but its use cogenerates hydrogen chloride, which can be undesirable.
• Ketene. At one time acetic anhydride was prepared by the reaction of ketene with acetic acid:{{citation | last = Arpe | first = Hans-Jürgen | title = Industrielle organische Chemie: Bedeutende vor- und Zwischenprodukte | url = https://books.google.com/books?id=36kHHvzx6M8C&dq=wacker+verfahren+essigs%C3%A4ureanhydrid&pg=PA200 | edition = 6th | publisher = Wiley-VCH | location = Weinheim | pages = 200–1 | isbn = 978-3-527-31540-6 | year = 2007 | language = German }}{{Dead link|date=July 2023 |bot=InternetArchiveBot |fix-attempted=yes }}

:{{chem2|H2C\dC\dO + CH3CO2H -> (CH3CO)2O}} $\backslash Delta\; H\; =\; -63\; \backslash text\{\; kJ/mol\}$

{{See also|Cellulose acetate}}

Cellulose is a polyol and thus susceptible to acetylation, which is achieved using acetic anhydride. Acetylation disrupts hydrogen bonding, which otherwise dominates the properties of cellulose. Consequently, the cellulose esters are soluble in organic solvents and can be cast into fibers and films.{{Ullmann |doi=10.1002/14356007.a05_419.pub2|title=Cellulose Esters|year=2004|last1=Balser|first1=Klaus|last2=Hoppe|first2=Lutz|last3=Eicher|first3=Theo|last4=Wandel|first4=Martin|last5=Astheimer|first5=Hans‐Joachim|last6=Steinmeier|first6=Hans|last7=Allen|first7=John M.|isbn=978-3-527-30385-4}}

{{See also|Acetylated wood}}

Acetylation of wood is a chemical modification process that enhances the properties of wood by making it highly resistant to fungi and insects, as well as very durable against moisture and environmental parameters.{{cite book|title=Springer Handbooks|publisher=Springer International Publishing|isbn=978-3-030-81314-7|year=2023|chapter=Springer Handbook of Wood Science and Technology|publication-place=Cham|page=897|issn=2522-8692|doi=10.1007/978-3-030-81315-4}}Holger Militz: [https://www.fawf.wald-rlp.de/fileadmin/website/fawfseiten/fawf/downloads/Projekte/Seeg/acetylierungsuebersicht.pdf Übersichtsbericht - Acetyliertes Holz - (Naturwissenschaftliche und technologische Grundlagen, materialtechnische und ökonomische Möglichkeiten und Grenzen, aktueller Stand der Umsetzung).] SGD Süd-Forstliche Versuchsanstalt Rheinland-Pfalz, 2011, accessed in December 2024.

The process involves the chemical reaction of acetic anhydride with the free hydroxyl groups in wood polymers, mostly of lignin and hemicelluloses, without requiring a catalyst. The modification results in bonds between the structural polymeric components, significantly reducing the ability of the -OH groups to form hydrogen bonds with water molecules. This effectively "locks" the cellular walls, minimizing the capacity of wood to absorb water and enhancing its dimensional stability. Approximately 80-90% of the hydroxyl groups of wood are modified during the process. The whole process is an environmentally friendly treatment, and has emerged, in the 21st century, as a significant innovation in the scientific area of wood science.{{cite journal | title=Wood modification technologies - a review | url=https://iforest.sisef.org/pdf/?id=ifor2380-010 | last1=Sandberg |first1=Dick |last2=Kutnar |first2=Andreja | author3-link=George Mantanis | author1-link=Dick Sandberg |last3=Mantanis |first3=George |journal=IForest |volume=10 |pages=895–908 |doi=10.3832/ifor2380-010 |date=2017-12-01 | issue=6 |access-date=2024-12-20|doi-access=free}}{{cite journal | last=Mantanis | first=George I. | author-link=George Mantanis | title= Chemical modification of wood by acetylation or furfurylation: A review of the present scaled-up technologies | journal=BioResources | volume=12 | issue=2 | date=2017 | doi= 10.15376/biores.12.2.Mantanis | pages=4478-4489| doi-access=free }}

Transacetylation uses vinyl acetate as an acetyl donor and lipase as a catalyst. This methodology allows the preparation of enantio-enriched alcohols and acetates.{{cite book |doi=10.1002/047084289X.rv008|chapter=Vinyl Acetate |title=Encyclopedia of Reagents for Organic Synthesis |year=2001 |last1=Manchand |first1=Percy S. |isbn=0471936235 }}

• Acetoxy group
• Acylation
• Amide
• Ester
• N-terminal acetylation
• Organic synthesis

{{Reflist|35em}}

Category:Organic reactions