Thioesterase: Difference between revisions

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'''Thioesterase''' is a type of [[enzyme]] that catalyzes the hydrolysis of [[thioester]] bonds. Thioester bonds are commonly found in many biological systems, including in the synthesis of [[fatty acids]] and [[polyketides]]. Thioesterases play a crucial role in these processes by terminating the elongation cycle of the fatty acid or polyketide chain.
{{Infobox enzyme
| name = Thioesterase
| image = <!-- Image removed -->
| width =
| caption =
| EC_number = 3.1.2
| CAS_number = 9023-79-8
| GO_code = 0016297
}}


== Structure and Function ==
'''Thioesterase''' is an [[enzyme]] that catalyzes the hydrolysis of [[thioester]] bonds, which are a type of [[ester]] bond formed between a [[carboxylic acid]] and a [[thiol]]. Thioesterases play a crucial role in various [[biochemical pathways]], including [[fatty acid metabolism]], [[polyketide synthesis]], and [[non-ribosomal peptide synthesis]].


Thioesterases are typically composed of a single polypeptide chain, with a catalytic triad consisting of a [[serine]], a [[histidine]], and an [[aspartic acid]] or [[glutamic acid]]. The serine acts as a nucleophile, attacking the carbonyl carbon of the thioester bond, while the histidine and aspartic acid or glutamic acid act as a base, deprotonating the serine and stabilizing the transition state.
== Function ==
Thioesterases are involved in the termination of [[fatty acid synthesis]] by hydrolyzing the thioester bond between the [[acyl carrier protein]] (ACP) and the growing fatty acid chain, releasing the free fatty acid. This reaction is essential for the production of [[lipids]] and [[membrane components]] in [[cells]].


Thioesterases are involved in a wide range of biological processes. In addition to their role in fatty acid and polyketide synthesis, they are also involved in the degradation of [[coenzyme A]] (CoA) esters, the regulation of [[signal transduction]] pathways, and the post-translational modification of proteins.
== Types ==
There are several types of thioesterases, each with specific functions and substrate specificities:


== Types of Thioesterases ==
* '''Type I Thioesterases''' - These are typically associated with [[fatty acid synthase]] complexes and are responsible for releasing the final product of the fatty acid synthesis cycle.


There are two main types of thioesterases: type I and type II. Type I thioesterases are involved in the termination of fatty acid synthesis, while type II thioesterases are involved in the termination of polyketide synthesis. Both types of thioesterases are found in a wide range of organisms, from bacteria to humans.
* '''Type II Thioesterases''' - These are standalone enzymes that can act on a variety of substrates, often involved in [[secondary metabolism]] such as [[antibiotic]] production.


== Clinical Significance ==
* '''Type III Thioesterases''' - These are less common and have unique roles in specific biosynthetic pathways.


Mutations in the genes encoding thioesterases can lead to a variety of diseases. For example, mutations in the gene encoding the thioesterase [[ACOT1]] have been associated with [[neurodegenerative diseases]] such as [[Alzheimer's disease]] and [[Parkinson's disease]]. Additionally, overexpression of the thioesterase [[FASN]] has been linked to [[cancer]], as it is involved in the synthesis of fatty acids, which are essential for cell growth and proliferation.
== Mechanism ==
Thioesterases catalyze the hydrolysis of thioester bonds through a nucleophilic attack on the carbonyl carbon of the thioester linkage. This reaction results in the formation of a [[carboxylate]] and a free thiol. The active site of thioesterases typically contains a [[serine]] or [[cysteine]] residue that acts as the nucleophile.


[[File:Thioesterase.png|thumb|right|300px|Structure of a thioesterase enzyme.]]
== Clinical Significance ==
Thioesterases are important in the development of [[therapeutic agents]] and [[biotechnology]] applications. Inhibitors of thioesterases are being explored as potential drugs for treating [[metabolic disorders]] and [[cancer]]. Additionally, engineered thioesterases are used in [[synthetic biology]] to produce [[biofuels]] and [[bioplastics]].


== See Also ==
== See Also ==
* [[Enzyme]]
* [[Enzyme]]
* [[Thioester]]
* [[Fatty acid metabolism]]
* [[Fatty acid synthesis]]
* [[Polyketide]]
* [[Polyketide synthesis]]
* [[Non-ribosomal peptide]]
* [[Coenzyme A]]
* [[Signal transduction]]
* [[Post-translational modification]]


== References ==
== References ==
{{Reflist}}


<references />
== External Links ==
* [https://www.wikimd.com/wiki/Thioesterase Thioesterase on WikiMD]


[[Category:Enzymes]]
[[Category:Enzymes]]
[[Category:Hydrolases]]
[[Category:Metabolism]]
[[Category:Biochemistry]]
[[Category:Biochemistry]]
[[Category:Molecular biology]]
[[Category:Cell biology]]
{{enzyme-stub}}
{{medicine-stub}}

Latest revision as of 20:48, 30 December 2024

Thioesterase






Thioesterase is an enzyme that catalyzes the hydrolysis of thioester bonds, which are a type of ester bond formed between a carboxylic acid and a thiol. Thioesterases play a crucial role in various biochemical pathways, including fatty acid metabolism, polyketide synthesis, and non-ribosomal peptide synthesis.

Function[edit]

Thioesterases are involved in the termination of fatty acid synthesis by hydrolyzing the thioester bond between the acyl carrier protein (ACP) and the growing fatty acid chain, releasing the free fatty acid. This reaction is essential for the production of lipids and membrane components in cells.

Types[edit]

There are several types of thioesterases, each with specific functions and substrate specificities:

  • Type I Thioesterases - These are typically associated with fatty acid synthase complexes and are responsible for releasing the final product of the fatty acid synthesis cycle.
  • Type II Thioesterases - These are standalone enzymes that can act on a variety of substrates, often involved in secondary metabolism such as antibiotic production.
  • Type III Thioesterases - These are less common and have unique roles in specific biosynthetic pathways.

Mechanism[edit]

Thioesterases catalyze the hydrolysis of thioester bonds through a nucleophilic attack on the carbonyl carbon of the thioester linkage. This reaction results in the formation of a carboxylate and a free thiol. The active site of thioesterases typically contains a serine or cysteine residue that acts as the nucleophile.

Clinical Significance[edit]

Thioesterases are important in the development of therapeutic agents and biotechnology applications. Inhibitors of thioesterases are being explored as potential drugs for treating metabolic disorders and cancer. Additionally, engineered thioesterases are used in synthetic biology to produce biofuels and bioplastics.

See Also[edit]

References[edit]

<references group="" responsive="1"></references>


External Links[edit]

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