acyl-CoA delta5-desaturase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: (8Z,11Z,14Z)-eicosatrienoyl-CoA + 2 Fe(II)-[cytochrome b5] + 2 H+ + O2 = (5Z,8Z,11Z,14Z)-eicosatetraenoyl-CoA + 2 Fe(III)-[cytochrome b5] + 2 H2O. Can also use a substrate with 3 double bonds (a (8Z,11Z,14Z,17Z)-eicosatetraenoyl-CoA) and add a fourth double bond (a (5Z,8Z,11Z,14Z,17Z)-eicosapentaenoyl-CoA). [PMID:10601301, PMID:10769175, RHEA:46424]

Acyl-CoA delta5-desaturase activity is a crucial enzymatic process that introduces a double bond between the fifth and sixth carbon atoms of a fatty acyl chain within a coenzyme A (CoA) ester. This desaturation reaction is catalyzed by a class of enzymes known as acyl-CoA delta5-desaturases, which are found in diverse organisms, including bacteria, fungi, plants, and animals. The reaction typically involves the oxidation of a saturated fatty acid, using molecular oxygen and reducing equivalents such as NADH or NADPH. This process results in the formation of a monounsaturated fatty acid, altering the physical properties of the lipid molecule, including its melting point and fluidity.

Acyl-CoA delta5-desaturase activity plays a critical role in various cellular processes, including:

* **Lipid synthesis:** The desaturation of fatty acids is an essential step in the biosynthesis of various lipids, including triglycerides, phospholipids, and sterols.
* **Membrane fluidity:** The incorporation of unsaturated fatty acids into cell membranes influences membrane fluidity, affecting membrane permeability, protein trafficking, and cellular signaling.
* **Hormone synthesis:** In animals, acyl-CoA delta5-desaturase activity is involved in the synthesis of steroid hormones like testosterone and estrogen.
* **Plant development:** In plants, this activity is critical for the production of polyunsaturated fatty acids, which are essential for membrane structure and function, as well as for the synthesis of signaling molecules like jasmonates.

The catalytic mechanism of acyl-CoA delta5-desaturases involves a complex series of steps that require the coordinated action of multiple cofactors and electron carriers. The enzyme typically contains a heme group and a non-heme iron center that facilitate the transfer of electrons from NADH or NADPH to molecular oxygen. The activated oxygen species then oxidizes the fatty acyl chain, resulting in the formation of a double bond.

Understanding the molecular function of acyl-CoA delta5-desaturase activity is crucial for elucidating the regulation of lipid metabolism, membrane dynamics, and cellular signaling. This enzyme is also a potential target for the development of novel therapies for diseases related to lipid metabolism, such as obesity, diabetes, and cardiovascular disease.'
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Proteins (1)

Compounds (3)