Fatty adds

Strictly speaking the term fatty add is restricted to those carboxylic acids that occur naturally in triacylglyc erols Many chemists and biochemists however refer to all unbranched carboxylic acids irrespective of their origin and chain length as fatty acids... 

R. W. Johnson and E. Fritz eds.. Fatty Adds in Industy, Marcel Dekker, Inc., New York, 1989. 

Fatty Adds in Food Saturated Versus Unsaturated... 

FIGURE 24.24 The oxidation pathway for polyunsaturated fatty adds, illustrated for linoleic add. Three cycles of /3-oxidation on linoleoyl-CoA yield the cis-A, d.s-A intermediate, which is converted to a tran.s-A, cis-A intermediate. An additional round of /S-oxi-dation gives d.s-A enoyl-CoA, which is oxidized to the trans-A, d.s-A species by acyl-CoA dehydrogenase. The subsequent action of 2,4-dienoyl-CoA reductase yields the trans-A product, which is converted by enoyl-CoA isomerase to the tran.s-A form. Normal /S-oxida-tion then produces five molecules of acetyl-CoA. 

FIGURE 25.9 Fatty add synthase in animals contains all the functional groups and enzyme activities on a single multifunctional subunit. The active enzyme Is a head-to-tall dimer of Identical subunits. (Adapted from Wakit, S. J., Stoops,... 

More than LOO different fatty acids are known, and about 40 occur widely. Palmitic acid (C ) and stearic acid (Cjy) are the most abundant saturated fatty adds oleic and linoleic acids (both Care the most abundant unsaturated ones. Oleic acid is monounsaturated since it has only one double bond, whereas linoleic, linolenic, and arachidonic acids are polyunsaturated fatty acids because they have more than one double bond. Linoleic and linolenic... 

One of the most striking features of the common fatty adds is that they have an even number of carbon atoms (Table 27.1, p. 1062). This even number results because all fatty acids are derived biosynthelically from acetyl CoA by sequential addition of two-carbon units to a growing chain. The acetyl CoA, in turn, arises primarily from the metabolic breakdown of carbohydrates in the glycolysis pathway that weTl see in Section 29.5. Thus, dietary carbohydrates consumed in excess of immediate energy needs are turned into fats for storage. 

Metabolites that are composed of structures of quite different oxidation states. Certain secondary metabolites and biosurfactants fell into this dass since they have both carbohydrates and fatty adds in their structures. 

Sophorolipid is a glycolipid, ie it is composed of carbohydrate and lipid. It therefore contains moieties of widely different oxidation levels and its synthesis from single demand carbon sources has a high ATP demand. However, the demand for ATP is reduced if a mixture of glucose and C-18 alkane is used. If glucose and fatty add is used the ATP demand is reduced further and relatively high spedfic production rates can be achieved. 

Quom has a higher ratio of polyunsaturated to saturated fatty add s than the other foods listed. It contains no cholesterol. The amino add profile is similar to that of other protein foods. It is slightly lower in methionine and cysteine content. 

Acceptable answers to part 1) indude amino adds and fatty adds or specific examples of each, such as glycine or stearic add respectively. The obvious answer for part 2) is the central metabolite pyruvate, though all of the adds of the TCA cycle would be appropriate. Answers to part 3) include the prindpal add of the hexose monophosphate... 

In the first two cases, the permeability of the cell membrane to L-glutamate is altered through changes in the fatty add composition of the cell membrane. In the third case, the degradation of the amino add is inhibited, resulting in accumulation. 

No discussion of the use of biotransfarmation in lipid chemistry would be complete without some mention of chemical transformation relating to fatty adds. Fatty adds are a major component of the lipid fraction of organisms. They are mainly found as components of triglycerides and phospholipids, although they may occur in smaller quantities as free fatty adds or as esters of other moieties. Fatty adds, either as free adds or as esters, are valuable commodities in the food and cosmetics industries. They may also serve as precursors of a variety of other compounds. 

Mixtures of triglycerides, triglycerides plus free fatty adds or triglycerides plus fatty acid alkyl esters are used as reactants in fat modification processes. These mixtures are exposed to lipases supported on macroporous particles in the presence of a small amount of water. Liquid substrates (oils) can be reacted without use of a solvent, but with solid reactants (fats) it is necessary to add a solvent to ensure that the reactants and products are completely dissolved in the organic phase. Various water immisdble solvents can be used, but hexane is preferred for commercial operation because this solvent is already used industrially for the processing of oils and fats. 

The fatty adds commonly encountered in biological systems are straight chained alkanoic or alkenoic adds, containing an even number of carbon atoms (usually Ch-Ch). natural n Senera / these fatty adds can be produced readily by extraction of the lipids from sources natural sources and saponifying the neutral triglycerides. This is satisfactory providing a mixture of fatty acids is acceptable. Purification of spedfic fatty adds from the saponification mixture increases the costs considerably. 

Considerable interest arose during the 1970 s and 1980 s in the use of micro-organisms to produce useful fatty adds and related compounds from hydrocarbons derived from the petroleum industry. During this period, a large number of patents were granted in Europe, USA and Japan protecting processes leading to the production of alkanols, alkyl oxides, ketones, alkanoic adds, alkane dioic acids and surfactants from hydrocarbons. Many of these processes involved the use of bacteria and yeasts associated with hydrocarbon catabolism. 

Prostaglandins are important derivatives of unsaturated fatty adds. Below we have drawn the structure of prostaglandin E2 as an illustration of the general structure of the prostaglandins. 

Malachite green (0.0...2.0) uradl derivatives, triazine herbiddes [163] polar lipids [246, 247] phospholipids [248, 249] fatty adds, fatty aldehydes, phospholipids and glycolipids [250] nticrobioddal isothiazolones [251]... 

Elongation of Fatty Add Chains Occurs in the Endoplasmic Reticulum... 

Figure 22-9. Regulation of ketogenesis. -(Dshow three crucial steps in the pathway of metabolism of free fatty adds (FFA) that determine the magnitude of ketogenesis. (CPT-I, carnitine palmitoyltransferase-l.)...

Free fatty adds in plasma are a major source of energy, particularly under marathon conditions and in prolonged starvation. 

Fig 1 Reacticm sequence for anaerobic decomposition of oiganic fatty adds consider Aa, Ba and Pa are yield coefSdents for respective decoiniosition reactiMis. 

These are the esters of long-chain fatty acids and long-chain fatty alcohols. Usually, only the alcohols are saturated and monoenoic, whereas the fatty adds may be more highly unsaturated, as in most marine waxes. They are found in both animal and plant tissues as well as in some microorganisms. They are quite common in insects. They reserve energy in aquatic animals, aid in echolocation, and play a vital role in waterproofing. 

Fatty acids of plant, animal, and microbial origin usually consist of an even number of carbon atoms in the straight chain. The number of carbon atoms of fatty adds in animals may vary from 2 to 36, whereas some microorganisms may contain 80 or more carbon atoms. Also, fatty adds of animal origin may have one to six ds double bonds, whereas those of higher plants rarely have more than three double bonds. Fatty adds also may be saturated, monounsaturated (monoenoic), or polyunsaturated (polyenoic) in nature. Some fatty acids may consist of branched chains, or they may have an oxygenated or cyclic structure. 

Phosphatidylcholine, commonly known as lecithin, is the most commonly occurring in natnre and consists of two fatty add moieties in each molecule. Phosphati-dylethanolamine, also known as cephahn, consists of an amine gronp that can be methylated to form other compounds. This is also one of the abundant phospholipids of animal, plant, and microbial origin. Phosphatidylserine, which has weakly acidic properties and is found in the brain tissues of mammals, is found in small amounts in microorganisms. Recent health claims indicate that phosphatidylserine can be used as a brain food for early Alzheimer s disease patients and for patients with cognitive dysfunctions. Lysophospholipids consist of only one fatty acid moiety attached either to sn-1 or sn-2 position in each molecule, and some of them are quite soluble in water. Lysophosphatidylchohne, lysophosphatidylserine, and lysophos-phatidylethanolamine are found in animal tissues in trace amounts, and they are mainly hydrolytic products of phospholipids. 

Tank Batch operation, small-scale production Fatty adds, vegetable oils, sugars... 

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