Fatty acids palmitic

FIGURE 3-7 Pathways for the interconversion of brain fatty acids. Palmitic acid (16 0) is the main end product of brain fatty acid synthesis. It may then be elongated, desaturated, and/or P-oxidized to form different long chain fatty acids. The monoenes (18 1 A7, 18 1 A9, 24 1 A15) are the main unsaturated fatty acids formed de novo by A9 desaturation and chain elongation. As shown, the very long chain fatty acids are a-oxidized to form a-hydroxy and odd numbered fatty acids. The polyunsaturated fatty acids are formed mainly from exogenous dietary fatty acids, such as linoleic (18 2, n-6) and a-linoleic (18 2, n-3) acids by chain elongation and desaturation at A5 and A6, as shown. A A4 desaturase has also been proposed, but its existence has been questioned. Instead, it has been shown that unsaturation at the A4 position is effected by retroconversion i.e. A6 unsaturation in the endoplasmic reticulum, followed by one cycle of P-oxidation (-C2) in peroxisomes [11], This is illustrated in the biosynthesis of DHA (22 6, n-3) above. In severe essential fatty acid deficiency, the abnormal polyenes, such as 20 3, n-9 are also synthesized de novo to substitute for the normal polyunsaturated acids. 

These points can be better appreciated by comparing the complete oxidation of glucose with that of a typical saturated fatty acid, palmitate. 

Acetogenins. Consistent with expectations based on the nature of the cotton plant, a number of fatty acids and related compounds have been characterized as components. Table I lists those which have been reported and which contain at least twelve carbon atoms in the linear chain. Much of such material is found in the seeds and in the waxes of the leaves and much is tied up as glyceride or as sterol ester W. Of these fatty acids, palmitic... 

Fatty acids (palmitic, oleic, linoleic acids) from unsaponifiables Silicalite-1 Acetone [179]... 

The end-product of this process is the C-16 saturated fatty acid, palmitate. The elongation of palmitate to longer-chain fatty acids involves another system (see below). 

Type V and Vi proteins carry lipid anchors. These are fatty acids (palmitic acid, myristic acid), isoprenoids (e.g., farnesol), or glycoli-pids such as glycosyl phosphatidylinositol (GPi) that are covalently bound to the peptide chain. 

The ultimate product of seven cycles of these reactions is the fully saturated, Cl6 fatty acid palmitate. 

FIGURE 21-12 Routes of synthesis of other fatty acids. Palmitate is the precursor of stearate and ionger-chain saturated fatty acids, as well as the monounsaturated acids palmitoleate and oleate. Mammals cannot convert oleate to linoleate or a-linolenate (shaded pink), which are therefore required in the diet as essential fatty acids. Conversion of linoleate to other polyunsaturated fatty acids and eicosanoids is outlined. Unsaturated fatty acids are symbolized by indicating the number of carbons and the number and position of the double bonds, as in Table 10-1. 

What can be done to prevent atherosclerosis For persons with a high LDL level there is little doubt that a decreased dietary intake of cholesterol and a decrease in caloric intake are helpful. While such dietary restriction may be beneficial to the entire population, controlled studies of the effect of dietary modification on atherosclerosis have been disappointing and confusing.33 A diet that is unhealthy for some may be healthy for others. For example, an 88-year old man who ate 25 eggs a day for many years had a normal plasma cholesterol level of 150-200 mg / deciliter (3.9-5.2 mM) bb Comparisons of diets rich in unsaturated fatty acids, palmitic acid, or stearic acid have also been confusing.cc cd/dd Can it be true that palmitic acid from tropical oils and other plant sources promotes atherogenesis, but that both unsaturated fatty acids and stearic acid from animal fats are less dangerous ... 

The degradation of fatty acids occurs by an oxidation process in the mitochondria. The breakdown of the 16-carbon saturated fatty acid, palmitate, occurs in blocks of two carbon atoms by a cyclical process. The active substrate is the acyl-CoA derivative of the fatty acid. Each cycle involves four discrete enzymatic steps. In the process of oxidation the energy is sequestered in the form of reduced coenzymes of FAD and NAD+. These reduced coenzymes lead to ATP production through the respiratory chain. The oxidation of fatty acids yields more energy per carbon than the oxidation of glucose because saturated fatty acids are in the fully reduced state. 

Thus, combination of one acetate starter unit with seven malonates would give the Ci6 fatty acid, palmitic acid, and with eight malonates the Ci8 fatty acid, stearic acid. Note that the two carbons at the head of the chain (methyl end) are provided by acetate, not malonate, whilst the remainder are derived from malonate, which itself... 

Brenner, R.R., Vazza, D.V. and De Tomas, M.E. (1963). Effect of a fat-free diet and of different dietary fatty acids (palmitate, oleate and linoleate) on the fatty composition of freshwater fish lipids. Journal of Lipid Research 4,341-345. 

Whole soybeans contain 360-370 g/kg CP, whereas soybean meal contains 410-500 g/kg CP depending on efficiency of the oil-extraction process and the amount of residual hulls present. The oil has a high content of the polyunsaturated fatty acids, linoleic (08 2) and linolenic (08 3) acids. It also contains high amounts of another unsaturated fatty acid, oleic (08 1) and moderate amounts of the saturated fatty acids, palmitic (06 0) and stearic (08 0). 

Fatty acyls FA Fatty acids and conjugates Octadecanoids Eicosanoids Docosanoids Fatty alcohols Fatty aldehydes Fatty esters 0 Fatty acid palmitic acid... 

Fig. 1. Structures of (a) a saturated fatty acid (palmitate, C16 0) (b) a mono-unsaturated fatty acid with the double bond in the cis configuration (palmitoleate, C16 1) (c) a mono-unsaturated fatty acid with the double bond in the trans configuration (C18 1) and (d) a polyunsaturated fatty acid (linoleate, C18 2).

An unusual structural feature from the inositol perspective is the derivatiza-tion of the 2-hydroxyl group of inositol by a long chain fatty acid (palmitic acid). In many mature GPI-proteins, the palmatoyl side chain is not present the palmatoyl chain is added during the biosynthesis of GPI and removed after the GPI anchor is attached to the protein during posttranslational modification. Although the wyo-isomer of inositol is the most prevalent form in GPI molecules, the presence of chiro-inositol has also been detected. 

Figure 12.2. Structures of Two Fatty Acids. Palmitate is a 16-carbon, saturated fatty acid, and oleate is an 18-carbon fatty acid with a single cis double bond.

The fatty acids which, together with glycerol, make up the fats (used mostly for energy storage) and the phospholipids (the major component of cell membranes). The 16 carbon fatty acid palmitate is shown below ... 

The leaves of higher plants contain upto 7% of their dry weight as fats some of which are present as surface lipids, the others as components of leaf cells, especially in the chloroplast membrane. The fatty acid composition of plant membrane lipids is very simple. Six fatty acids- palmitic, palmitoleic, stearic, oleic, linoleic and y-linolenic generally account for over 90% of the total fatty acids. 

FIGURE 231 Structure of the 16 aibon fatty acid palmitic acid. 

Figure 2.51 shows the structure of the 16-carbon fatty acid palmitic add. In the triglyceride and phospholipid structures shown in Figure 2,32, R, R, and represent the alkane "tails" of fatty adds. The fatty acid compositions of the phospholipids and triglycerides of various foods are listed in Table 2-2-...

FIGURE 636 Conversion of palmitic acid to an 18 1 fatty acid. Palmitic acid (16 0), a saturate, is converted in the bnily to the monounsatuTatcacLd (18 1) by a twcnslcp process involving ini fiat conversion to stearic acid (18 0). 

This reference documented chromatographic characteristics for many individual additives including plasticizers (phthalates, Citroflex A-4, TNPP) amides Irganox and Irgafos antioxidants UV absorbers (Tinuvin, Cyansorb) fatty acids (palmitic, stearic) Naugard XL-1 etc. 

Both plants and animals make waxes. Plant leaves are often coated with wax, which prevents water loss. Notice in Figure 24-15 how raindrops bead up on the leaves of a plant, indicating the presence of the waxy layer. The honeycomb of bees also is made of a wax, commonly called beeswax. Combining the 16-carbon fatty acid palmitic acid and a 30-carbon alcohol chain makes a common form of beeswax. Candles are sometimes made of beeswax because it burns slowly and evenly. 

Draw the structure of the soap sodium palmitate (pahnitate is the conjugate base of the 16-carbon sam-rated fatty acid, palmitic acid) and label its polar and nonpolar ends. (24.3)... 

The fatty acid palmitic acid has a density of 0.853 g/mL at 62°C. What will be the mass of a 0.886-L sample of palmitic acid at that temperature ... 

The synthesis of one mole of the fatty acid palmitic acid from two-carbon bnilding blocks reqnires seven moles of ATP. How many kJ of energy are reqnired for the synthesis of one mole of palmitic acid ... 

Behavioral Diet Saturated fatty acids (palmitic acid) NC +... 

Properties A drying oil similar in properties and uses to linseed. Edible, iodine value approximately 160, d 0.923, refr index 1.470-1.472. Contains approximately 10% saturated fatty acids (palmitic and stearic), unsaturated acids present are linoleic, lin-olenic, and oleic. Saponification value 190-193. 

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