What is thioester hydrolysis?
Hydrolysis of thioesters The acyl group of a thioester can be transferred to a water molecule in a hydrolysis reaction, resulting in a carboxylate. An example of thioester hydrolysis is the conversion of (S)-citryl CoA to citrate in the citric acid cycle (also known as the Krebs cycle).
What is the role of thioester in glycolysis?
A thioester directly linked to a protein via a cysteine residue is generated in the course of the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase (GAPDH), an enzyme of glycolysis.
Are thioesters reactive?
A thioester is more reactive than an ester, for example, because a thiolate (RS-) is a weaker base and better leaving group than an alcoxide (RO-). Thioesters, for example, are often converted directly into carboxylic esters in biochemical reactions, but not the other way around.
Can thioester form hydrogen bonds?
The SH stretch band of the SH···O complex is red-shifted and undergoes significant intensity enhancement compared to the bare molecule, which is characteristic of hydrogen bonding. These findings offer insight into the nature of the thiol functional group as a potential hydrogen bond donor and acceptor.
How is thioester used?
Thioesters are involved in the synthesis of all esters, including those found in complex lipids. They also participate in the synthesis of a number of other cellular components, including peptides, fatty acids, sterols, terpenes, porphyrins, and others.
What is thioester linkage?
Definition. Thioester‐linkage (or thioester bond) defines a very labile ester‐bond between the COOH‐group of a fatty acid and a ‐SH‐group of a cysteine residue in the polypeptide chain (S‐Acylation).
What is the importance of the thioester?
What is a thioester bond?
Is thioester a functional group?
Thioester (thiolester): A functional group characterized by a sulfur atom flanked by one carbonyl group and one carbon of any hybridization.
Is soap a thioester?
Soap is composed primarily of ‘fatty acid’ molecules, which are actually carboxylates with long carbon chains. Acetyl-CoA, a very important molecule in metabolism, is characterized by its thioester group (it also contains two amide groups – can you find them?).
What are thioester bonds?
Definition. Protein which is posttranslationally modified by the formation of a thioester crosslink between two amino acids in the polypeptidic chain(s), usually formed between a cysteine side chain and the carboxamide group of an asparagine or glutamine side chain.
Does thioester have resonance?
The thioester bond is a high energy bond. This is apparently because resonance structures which can occur in esters with alcohols, and which stabilizes them, cannot occur in thioesters. The greater size of the sulfur atom (compared to the carboxyl oxygen) diminishes the stability of the resonance forms.
What is thiol–thioester exchange?
Thiol–thioester exchange—the reaction between a thioester and a thiolate anion to produce a new thioester and thiolate as products—is one possible constructive reaction of thioesters on early Earth.
What are some examples of thioesters?
In biochemistry, the best-known thioesters are derivatives of coenzyme A, e.g., acetyl-CoA. The most typical route to thioester involves the reaction of an acid chloride with an alkali metal salt of a thiol:
What is the thermal decomposition of thioesters?
Thermal decomposition of thioesters is similar to that of the normal esters. β-Elimination reactions for thiono esters, thiol esters, and xanthates are schematically indicated below: The efficiency of β-elimination reactions for thioesters depends on the specific compound pyrolyzed, and the yield for the β-elimination can vary considerably [1].
Why do thioesters react better than oxygen esteres?
We seek a thermodynamic and kinetic account for this observation. Thermodynamically, the thioester linkage releases more free energy upon hydrolysis than an oxygen ester. Kinetically, the reactivity of a thioester at the alpha carbon compares favorably with that of ketones.