What are thioesters in biochemistry?
Thioesters are esters in which the linking oxygen atom is replaced by sulfur. They are the product of dehydration reaction between a carboxylic acid derivative and a thiol. Thioesters are common intermediates in biochemistry, for example, in acetyl-CoA, malonyl-CoA, acetoacetyl-CoA, and propionyl-CoA.
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 another name of ester interchange reaction?
What is the other name of ester-interchange reaction? Explanation: In the alcoholysis or ester-interchange reaction, an alcohol reacts with an ester to give a new ester. 2.
Why are thioesters used in metabolism?
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.
Why are thioesters more reactive than esters?
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-). Recall from chapter 7 that the pKa of a thiol is about 10, while the pKa of an alcohol is 15 or higher: a stronger conjugate acid means a weaker conjugate base.
Are thioesters reactive?
A thioester was shown to be at least 2000-fold more reactive than the equivalent oxoester toward reaction with the ethylcyanoacetate carbanion. Likewise, more than 100-fold greater reactivity of a thioester vs an oxoester has been observed in reaction with a thiolate nucleophile.
Why is thioester more reactive than ester?
Why is thioester hydrolysis favorable?
Because carboxylates are the least reactive among the carboxylic acid derivatives, these hydrolysis reactions are thermodynamically favorable, with thioester hydrolysis the most favorable of the three.
What kind of reaction is esterification?
Esterification. Esterification is a reaction type that produces an ester. In this case, we react a carboxylic acid with an alcohol to produce an ester and water. This is a reversible reaction, meaning both the forward reaction and the backward reaction happen at the same time in a state of dynamic equilibrium.