Fatty acid: coenzyme A ligases

Acyl-CoA synthetases are enzymes (i.e., ligases) that convert fatty acid molecules into acyl-Coenzyme A molecules for their subsequent oxidation. 

This enzyme [EC 6.2.1.15], also known as arachido-nateiCoA ligase, catalyzes the reaction of arachidonate with ATP and coenzyme A to generate arachidonyl-CoA, AMP, and pyrophosphate (or, diphosphate). The enzyme can also use 8,11,14-icosatrienoate as a substrate, but not the other long-chain fatty acids. It should be noted that this enzyme is not identical to long-chain acyl-CoA synthetase [EC 6.2.1.3]. 

In firefly luciferase reaction, the luminescence activity is enhanced by addition of Coenzyme A (CoA) and this phenomenon is explained by release of product inhibition. Also, firefly luciferase shows the sequence similarity to mammalian fatty acyl-CoA synthetase (AcCoAS) and plant 4-coumarate CoA ligase (4CL). They are classified as an adenylation enzyme for synthesizing acyl-CoA derivatives fi om carboxylic acid compounds in the presence of CoA, ATP and Mg (Scheme 1). Furthermore, it was reported that the luminescence activity of firefly luciferase is inhibited competitively by various long-chain fatty acids. We have determined that firefly luciferase is a bi-functional enzyme, catalyzing both the luminescence reaction and fatty acyl-CoA synthetic reaction. ... 

Fatty acyl-CoA ligases (specific for short, medium, or long chain fatty acids) catalyze formation of fatty acyl thioester conjugate with coenzyme A (Diagram)... 

Resveratrol biosynthesis branches from the phenylpropanoid pathway. The resveratrol biosynthesis pathway consists of four enzymesrphenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), 4-coumarate CoA ligase (4CL), and stilbene synthase (STS). The first two enzymes of the pathway, PAL and C4H, convert phenylalanine into /)-coumaric acid. The third enzyme, 4CL, attaches /)-coumaric acid to the pantetheine group of coenzyme-A (CoA) to produce 4-coumaroyl-CoA. The fourth enzyme, STS, catalyzes the condensation of resveratrol from one molecule of 4-coumaroyl-CoA and three molecules of malonyl-CoA, which originate from fatty acid biosynthesis. TAL is homologous to PAL and converts the amino acid tyrosine directly into / -coumaric acid. Methylated resveratrol derivatives of pinostilbene and pterostilbene are produced by resveratrol O-methyltransferase (ROMT) from resveratrol [135] (Figure 10.10). 

Biochemically, fatty acids are rather nonreactive molecules unless they are first activated by thioesteri-fication to coenzyme A (CoA). This reaction is catalyzed by acyl-CoA synthetases (also known as acid CoA ligases, E.C. 6.2.1.x). The overall acyl-CoA synthetase reaction is... 

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