Diunsaturated fatty acids

Liu W., Jiao H., Murray N. C., O Conner M. and Roelofs W. L. (2002) Gene characterized for membrane desaturase that produces ( )-11 isomers of mono- and diunsaturated fatty acids. Proc. Natl. Acad. Sci. USA 99, 620-624. 

The reactions mentioned above account for many, but by no means all, pheromones whose biosynthesis is related to fatty acids. For example, the silkworm moth, Bombyx mori, has as its main pheromone component E, Z)-10,12-hexadecadien-l-ol (1). The corresponding diunsaturated fatty acid also is present in the gland (JjL), as is a large quantity of (Z) -11-hexadecenoic acid (15.). Recent studies have demonstrated that the monounsaturated acid is formed first, followed by what appears to be a 1,4-desaturation yielding the diunsaturated acid (1 ). 

Figure 22.10. Oxidation of Linoleoyl CoA. The complete oxidation of the diunsaturated fatty acid linoleate is facilitated by the activity of enoyl CoA isomerase and 2,4-dienoyl CoA reductase.

An 18-carbon saturated fatty acid yields 120 ATP. For a diunsaturated fatty acid with the bonds in the A and positions, the first double bond eliminates an FADHg. The second double bond uses an NADPH, which we are guessing is the same cost as using an NADH. Thus a total of 4 ATP are lost, compared with a saturated fatty acid, so the total is 116 ATP. 

In attempting to answer this question, let us first of all consider the extent of variation in the intake of essential fatty acids likely to be encountered in different countries of the world. Data compiled by the Food and Agriculture Organization of the United Nations (1971) indicate that the fat component of human diets may contribute anywhere from just over 10% to more than 40% of the total calories. The various fats and oils that go to make up this dietary fat differ widely in their content of linoleic acid, the major dietary essential fatty acid. The diunsaturated (18 2) fatty acid content of different dietary fats and oils is shown in Table 2. In some cases, this is not all linoleic acid (e.g. butter contains only about 0.8% linoleic acid), but in most cases, the diunsaturated fatty acid can be equated with linoleic acid. Animal fats generally contain less linoleic acid than plant fats, but there is considerable overlap, as seen in Table 2. 

The lipid composition of adipose tissue in NMRI and NMRI nu/nu mice has been measured by NMR. A voxel size of 1.5 mm x 1.5 mm x 1.5 mm was used to collect spectra without water suppression. The relative amounts of saturated, monounsaturated, and polyunsaturated fatty acids were measured after correction for T2 relaxation in intra-abdominal white adipose tissue and brown adipose tissue deposits. The composition of brown adipose tissue in NMRI mice was significantly different from brown adipose tissue in NMRI nu/nu mice except for the fraction of monounsaturated fatty adds. However, in white adipose tissue only the fraction of monounsaturated fatty acids was significantly different between NMRI and NMRI nu/nu mice. Brown adipose tissue and white adipose tissue of NMRI mice differed in the amount of saturated and diunsaturated fatty acids. 

Chemical synthesis of the palmitoyl- and stearoyl-derivatives of dihydrosphingomyelin confirmed this structure (Shapiro et al. 1958). Long chain saturated fatty acids, mono- and even diunsaturated fatty acids (predominantly stearic, lignoceric and nervonic acids) have been isolated from sphingomyelin, but no hydroxy fatty acids (Sweeley 1963 Kishimoto et al. 1963 O Brien et al. 1964). 

Triimsaturated fatty acids, such as linolenic acid, are much more rapid in forming oxidative crosslinks than diunsaturated fatty acids, such as linoleic acid. Conjugated, triimsaturated fatty acids, such as eleostearic acid, are faster yet. 

Argentation—GLC Individual trans fatty acids Saturated, monounsaturated, and diunsaturated fatty acids can be resolved Method is time-consuming... 

This chapter focuses on the preparation of thermosets, polyesters, and other polymers from industrial oilseeds. Nature has provided a few examples of plant oils that possess multiple functional groups needed for polymer synthesis, such as castor (Ricinus communis), lesquerella (Lesquerella fendleri), and vemonia (Vernonia galamensis) oils, enriched in —OH and epoxide-functionalized fatty acids ricinoleic, lesquerolic, and vemolic acid, respectively (Table 3.1). Many common plant seed oils (eg, soybean, cottonseed, com, soybean, safQower, sunflower, canola, jatropha, and olive oils) are enriched in Ci6—Cig saturated and mono- and diunsaturated fatty acids, such as palmitic (16 0), oleic (18 l-9c), and linoleic (18 2-9c,12c) acids and lesser amounts of a-linolenic acid (18 3-9c,12c,15c) however, linseed (flaxseed), camelina (Camelina saliva). 

Table 19.9 , -Diunsaturated fatty acids of Plakortis halichondroides...

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