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Fatty acyl-CoA esters are fatty acid derivatives formed of one fatty acid, a 3'-phospho-AMP linked to phosphorylated pantothenic acid (vitamin B 5) and cysteamine. Long-chain acyl-CoA esters are substrates for a number of important enzymatic reactions and play a central role in the regulation of metabolism as allosteric regulators of several ...
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.
acyl-P + HS-CoA → acyl-S-CoA + P i + H + Three types of acyl-CoA synthases are employed, depending on the chain length of the fatty acid. [3] For example, the substrates for medium chain acyl-CoA synthase are 4-11 carbon fatty acids. [4] The enzyme acyl-CoA thioesterase takes of the acyl-CoA to form a free fatty acid and coenzyme A. [4]
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.
Fatty acids are first converted to acyl-CoA. Acyl-CoA is then degraded in a four-step cycle of oxidation, hydration, oxidation and thiolysis catalyzed by four respective enzymes, namely acyl-CoA dehydrogenase, enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase, and thiolase. The cycle produces a new fatty acid chain with two fewer carbons and ...
Thiolases are a family of evolutionarily related enzymes.Two different types of thiolase [4] [5] [6] are found both in eukaryotes and in prokaryotes: acetoacetyl-CoA thiolase (EC 2.3.1.9) and 3-ketoacyl-CoA thiolase (EC 2.3.1.16). 3-ketoacyl-CoA thiolase (also called thiolase I) has a broad chain-length specificity for its substrates and is involved in degradative pathways such as fatty acid ...
The acyl-CoA breaks at the thioester bond, forming a CoA and carboxylic acid. The carboxylic acid remains bound to the enzyme, but it is soon displaced by CoA and leaves. A new carboxylic acid (the CoA acceptor) enters and forms a new acyl-CoA. The new acyl-CoA is released, completing the transfer of CoA from one molecule to another.
Acyl-CoA dehydrogenases are enzymes that catalyze formation of a double bond between C2 (α) and C3 (β) of the acyl-CoA thioester substrates. [20] Flavin adenine dinucleotide (FAD) is a required co-factor.