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The acetyl group (indicated in blue in the structural diagram on the right) of acetyl-CoA is linked to the sulfhydryl substituent of the β-mercaptoethylamine group. This thioester linkage is a "high energy" bond, which is particularly reactive. Hydrolysis of the thioester bond is exergonic (−31.5 kJ/mol).
Acyl-CoA is a group of CoA-based coenzymes that metabolize carboxylic acids. Fatty acyl-CoA's are susceptible to beta oxidation, forming, ultimately, acetyl-CoA. The acetyl-CoA enters the citric acid cycle, eventually forming several equivalents of ATP. In this way, fats are converted to ATP, the common biochemical energy carrier.
In biochemistry and metabolism, beta oxidation (also β-oxidation) is the catabolic process by which fatty acid molecules are broken down in the cytosol in prokaryotes and in the mitochondria in eukaryotes to generate acetyl-CoA. Acetyl-CoA enters the citric acid cycle, generating NADH and FADH 2, which are electron carriers used in the ...
The thioester bond is a high energy bond. [1] The activation reaction normally occurs in the endoplasmic reticulum or the outer mitochondrial membrane. This is an adenosine triphosphate (ATP)-requiring reaction with fatty acyl-CoA synthase (CoASH), yielding adenosine monophosphate (AMP) and pyrophosphate (PPi): [2]
High plasma levels of insulin in the blood plasma (e.g. after meals) cause the dephosphorylation of acetyl-CoA carboxylase, thus promoting the formation of malonyl-CoA from acetyl-CoA, and consequently the conversion of carbohydrates into fatty acids, while epinephrine and glucagon (released into the blood during starvation and exercise) cause ...
Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle.All genomes sequenced to date encode enzymes that use coenzyme A as a substrate, and around 4% of cellular enzymes use it (or a thioester) as a substrate.
Examples include malonyl-CoA, acetoacetyl-CoA, propionyl-CoA, cinnamoyl-CoA, and acyl carrier protein (ACP) thioesters. Acetogenesis proceeds via the formation of acetyl-CoA . The biosynthesis of lignin , which comprises a large fraction of the Earth's land biomass, proceeds via a thioester derivative of caffeic acid . [ 11 ]
Acetyl-CoA synthetase (ACS) or Acetate—CoA ligase is an enzyme (EC 6.2.1.1) involved in metabolism of acetate. It is in the ligase class of enzymes, meaning that it catalyzes the formation of a new chemical bond between two large molecules.