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In addition, acetyl-CoA is a precursor for the biosynthesis of various acetyl-chemicals, acting as an intermediate to transfer an acetyl group during the biosynthesis of those acetyl-chemicals. Acetyl-CoA is also involved in the regulation of various cellular mechanisms by providing acetyl groups to target amino acid residues for post ...
ATP + Acetate + CoA → AMP + Pyrophosphate + Acetyl-CoA [1] Once acetyl-CoA is formed it can be used in the TCA cycle in aerobic respiration to produce energy and electron carriers. This is an alternate method to starting the cycle, as the more common way is producing acetyl-CoA from pyruvate through the pyruvate dehydrogenase complex.
The mevalonate pathway of eukaryotes, archaea, and eubacteria all begin the same way. The sole carbon feed stock of the pathway is acetyl-CoA. The first step condenses two acetyl-CoA molecules to yield acetoacetyl-CoA. This is followed by a second condensation to form HMG-CoA (3-hydroxy-3- methyl-glutaryl-CoA). Reduction of HMG-CoA yields (R ...
First, a CoA group is enzymatically transferred to it from succinyl CoA, converting it back to acetoacetyl CoA; this is then broken into two acetyl CoA molecules by thiolase, and these then enter the citric acid cycle. Heart muscle and renal cortex prefer acetoacetate over glucose.
Two specific enzymes participate on the carbon monoxide side of the pathway: CO dehydrogenase and acetyl-CoA synthase. The former catalyzes the reduction of the CO 2 and the latter combines the resulting CO with a methyl group to give acetyl-CoA. [2] [1] [3] Some anaerobic bacteria use the Wood–Ljungdahl pathway in reverse to break down acetate.
In biological organisms, acetyl groups are commonly transferred from acetyl-CoA to other organic molecules. Acetyl-CoA is an intermediate in the biological synthesis and in the breakdown of many organic molecules. Acetyl-CoA is also created during the second stage of cellular respiration (pyruvate decarboxylation) by the action of pyruvate ...
It is created from acetyl-CoA, a thioester, which reacts with the enolate of a second molecule of acetyl-CoA in a Claisen condensation reaction, [2] and it is acted upon by HMG-CoA synthase to form HMG-CoA. [1] During the metabolism of leucine, this last reaction is reversed. Some individuals may experience Acetoacetyl-CoA deficiency. [3]
However, if the amounts of acetyl-CoA generated in fatty-acid β-oxidation challenge the processing capacity of the TCA cycle; i.e. if activity in TCA cycle is low due to low amounts of intermediates such as oxaloacetate, acetyl-CoA is then used instead in biosynthesis of ketone bodies via acetoacetyl-CoA and β-hydroxy-β-methylglutaryl-CoA .