Fatty acid desaturase 3 FADS

F26BP, fructose-2,6-bisphosphate FA, fatty acid FAD, fatty acid desaturase FADH2/FAD, reduced/oxidized flavin adenine dinucleotide F -ATPase, ATP synthetase F complex FGF, fibroblast growth factor FGF-RTK, fibroblast growth factor receptor tyrosine kinase Fmet, formylmethionine FMNH2/FMN, reduced/oxidized flavin mononucleotide... 

These fatty acids are formed by desaturation of saturated fatty acids. The process occurs after the release of the saturated fatty acid from fatty acid synthase, and it requires a special enzyme, fatty-acid desaturase, which uses FAD as a cofactor. The enzyme only creates —C=C— double bonds between carbon atoms less than nine away from the carboxyl end. Thus many nutritionally important unsaturated fatty acids that contain double bonds at higher positions along their carbon chain, such as linolenic acid, which is unsaturated at the C9, C12, and Cl5, must be derived from the diet. Such fatty acids are called essential, as is the case for those amino acids for which there is an obligatory requirement in the diet. 

Tomato Rapeseed/ overexpression CaMV35S/ FADS, FAD7 00-3 fatty acid desaturase Linolenic acid (18 3) Higher 18 3/ 18 2 ratio [161]... 

Iba K, Gibson S, Nishiuchi T, Fuse T, Nishimura M, Arondel V, Hugly S, Somerville C. A gene encoding a chloroplast co-3 fatty acid desaturase complements alterations in fatty acid desaturation and chloroplast copy number of the fad mutant of Arabidopsis thaliana. J Biol Chem 1993 268 24099-24105. 

The mechanism of fatty acid unsaturation (e.g., stearic acid — oleic acid) utilizes a system similar to that involving cytochrome P-450 (Chapter 17) it is micro-some bound, and it includes a heme-containing protein (cytochrome b5), an FAD-containing reductase, and an iron-sulfur center-containing "desaturase." The electron source is NADH or NADPH. Equation (19.14) summarizes this process ... 

DuPont scientists were the first to clone FAD2 and FADS genes from the soybean (2). They also provided conclusive evidence for the mechanism of polyunsaturated fatty acid biosynthesis, when antisense or cosuppression of the FAD2 gene led to lower n-6 desaturase activity, and the accumulation of oleic acid in glycerolipids. This was demonstrated not only in soybeans, but also in other oilseed crops, such as canola and sunflower (Table 1). These transgenic events... 

We also observed a novel fatty acid in some of the high oleic lines. This fatty acid was an isomer of linoleic acid, 9,15 octadecanoic acid, and was probably the result of omega-3 desaturase (Fad 3) activity on oleic acid, since the normal substrate for this enzyme was not present in these plants (this isomer can be reduced or eliminated by crossing the Fad 2-1 plants with plants containing a suppressed Fad 3 gene). The 9,15 octadecanoic acid has not be detected in soybeans with a normal oleic acid content but it is found in many other foodstuffs (from about 5% in mango pulp to about 0.5% in human milk) and... 

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