Hydrolysis of the thioester bond is exergonic (−31.5 kJ/mol). CoA is acetylated to acetyl-CoA by the breakdown of carbohydrates through glycolysis and by the breakdown of fatty acids through β-oxidation.

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. Acetogenesis proceeds via the formation of acetyl-CoA.

Coenzyme A, abbreviated CoA, is a thiol formed by a phosphoric anhydride linkage (O═P–O–P═O O═P–O–P═O) between phosphopantetheine and adenosine 3′,5′-bisphosphate. (The prefix bis - means “two” and indicates that adenosine 3′,5′-bisphosphate has two phosphate groups, one on C3′ and one on C5′.)

Coenzyme A is often abbreviated HSCoA, in order to emphasize that it is the thiol sulfur that provides the critical thioester linkage to acyl groups. When fuel (carbohydrate and fat) is broken down in your body, it is eventually converted to a simple two-carbon unit called acetyl CoA, which is essentially a thioester derivative of acetic acid:

In the citrate synthase reaction, a thioester bond is formed between the sulfur atom of Coenzyme A and the carbonyl carbon of acetyl-CoA. This high-energy thioester bond allows the acetyl group to be readily transferred to the oxaloacetate molecule, initiating the citric acid cycle.

Acetyl-CoA is a membrane-impermeant molecule constituted by an acetyl moiety (CH 3 CO) linked to coenzyme A (CoA), a derivative of vitamin B 5 and cysteine, through a thioester bond (Shi and Tu, 2015).

Acetyl-CoA is formed by the acetylation of coenzyme A, which consists of an acetyl group linked to a cysteine residue of coenzyme A through a high-energy thioester bond. [7] Acetyl-CoA is mainly distributed in mitochondria, cytosol and nuclear solute in cells.

2015年6月2日 · As thioester bonds are energy rich, the chemical structure of acetyl-CoA facilitates the transfer of the acetyl moiety to a variety of acceptor molecules, including amino groups on proteins (Shi and Tu, 2015). Acetylation can occur as a co-translational event.

2016年12月10日 · The central metabolite acetyl CoA is a thioester that is produced mainly by oxidative decarboxylation of pyruvate or by fatty acid degradation. The primary fates of acetyl CoA are to enter the citric acid cycle or to contribute to fatty acid synthesis.

2020年7月1日 · Thioesterases are a large superfamily of enzymes that play important cellular roles. They catalyse the cleavage of thioester bonds that are present in a wide range of activated fatty acyl-coenzyme A (CoA) substrates, acyl-carrier proteins (ACPs), glutathione, and other cellular molecules (Fig. 1).