Can thioesters be reduced?
3.2 Reduction of Thioesters. Thioesters can be deprotected by acidic or basic hydrolysis to give thiols, but, due to the sensitivity of some substrates under these conditions, alternative reductive methods can be employed.
What is an example of thioester?
Thioesters are common intermediates in many biosynthetic reactions, including the formation and degradation of fatty acids and mevalonate, precursor to steroids. Examples include malonyl-CoA, acetoacetyl-CoA, propionyl-CoA, cinnamoyl-CoA, and acyl carrier protein (ACP) thioesters.
What does the A stand for in Acetyl-CoA?
acetyl coenzyme A
Infobox references. Acetyl-CoA (acetyl coenzyme A) is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for energy production.
What is the role of the thioester in this reaction?
Thioesters play a prominent role in metabolism. This is especially true of fatty acid metabolism. The central metabolite acetyl CoA is a thioester that is produced mainly by oxidative decarboxylation of pyruvate or by fatty acid degradation.
Can thioesters be hydrolyzed?
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).
Do thioesters smell?
The diverse aroma quality of thioesters containing two- to six-carbon chain lengths has ranged from “cheesy” to “green,” “floral” to “pineapple” odor for methyl thiohexanoate [5].
Why are thioesters good donors of acyl groups what exactly are thioesters?
Furthermore, the C-S bond is weaker than the C-O bond, and the thiolate (or thiol, if protonated) is a better leaving group than alkoxide (or alcohol). These factors all make a thioester in general a better acylating agent than an ester.
How do you make ester hydrolysis?
To make the hydrolysis as complete as possible, you would have to use an excess of water. The water comes from the dilute acid, and so you would mix the ester with an excess of dilute acid. Note: These reactions are exactly the reverse of those used to make an ester from a carboxylic acid and an alcohol.
What is the functional group of thioester?
In chemistry thioesters are compounds with the functional group R–S–CO–R’. They are analogous to carboxylate esters with the sulfur in the thioester playing the role of the linking oxygen in the carboxylate ester. They are the product of esterification between a carboxylic acid and a thiol.
What is the difference between an ester and a thioester?
The key difference between ester and thioester is that ester compounds contain carbon, hydrogen and oxygen atoms whereas thioester compounds contain carbon, hydrogen, oxygen and sulfur atoms.
How is a carboxyl group converted to a thioester?
The conversion of a carboxyl group to a thioester occurs in biochemical reactions by four main routes: (1)Esterification of a carboxyl group, driven by ATP hydrolysis (as shown above) (2)Oxidative decarboxylation of an α-keto acid.
How is a thioester formed?
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. Formation of thioesters The conversion of a carboxyl group to a thioester occurs in biochemical reactions by four main routes: