unsaturated fatty acid biosynthetic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the formation of an unsaturated fatty acid, any fatty acid containing one or more double bonds between carbon atoms. [GOC:mah, MetaCyc:PWY-762, MetaCyc:PWY-782]

The biosynthesis of unsaturated fatty acids is a crucial process in all living organisms, particularly in eukaryotes. This complex pathway involves a series of enzymatic reactions that introduce double bonds into saturated fatty acid chains, thereby generating essential components of cell membranes, signaling molecules, and energy stores.

The process typically begins with the formation of a saturated fatty acid, such as palmitic acid (16:0). This saturated fatty acid serves as the substrate for the introduction of double bonds. Key enzymes involved in the process include fatty acyl-CoA desaturases (FADS). These desaturases utilize molecular oxygen and NADH to catalyze the formation of a double bond between specific carbon atoms in the fatty acid chain.

In humans, FADS1 and FADS2 are critical enzymes for the synthesis of polyunsaturated fatty acids (PUFAs). FADS1 introduces the first double bond at the Δ9 position, producing oleic acid (18:1). FADS2 then introduces a second double bond at the Δ6 position, leading to linoleic acid (18:2). These reactions occur in the endoplasmic reticulum of cells.

Once linoleic acid (18:2) is synthesized, it can be further elongated and desaturated by other enzymes to produce longer-chain PUFAs, such as arachidonic acid (20:4), which is essential for prostaglandin biosynthesis and signaling. Likewise, alpha-linolenic acid (18:3) can be elongated and desaturated to produce eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are crucial for brain and retinal development.

The biosynthesis of unsaturated fatty acids is tightly regulated, ensuring an appropriate balance of saturated and unsaturated fatty acids in cell membranes and tissues. This regulation involves factors like enzyme availability, substrate concentrations, and cellular signals. Deficiencies in specific desaturases or alterations in their activities can lead to metabolic disorders and developmental abnormalities.

Unsaturated fatty acids play vital roles in maintaining cell membrane fluidity, regulating gene expression, contributing to the immune response, and serving as precursors for various bioactive molecules. Their biosynthesis is an essential process for life, highlighting the importance of dietary sources of unsaturated fatty acids and the complex enzymatic machinery that ensures their production.'
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Proteins (4)

Compounds (4)