Fatty acids requirements

Degradation of Polyunsaturated Fatty Acids Requires 2,4-Dienoyl-CoA Reductase... 

Andreasen A. A. Stier J.B. (1954) Anaerobic nuliition of Saccharomyces cerevisiae. II. Unsaturated fatty acid requirement for growth in a defined medium. J Cell Comp Physiol, 43, 271 -281. 

Hafner, E.W., Holley, B.W., Holdom, K.S. et al. (1991) Branched-chain fatty acid requirement for avermectin production by a mutant of Streptomyces avermitilis lacking branched-chain 2-oxo acid dehydrogenase activity. Journal of Antibiotics (Tokyo), 44, 349-356. 

The box shows fatty acid synthesis which may occur within the adipocyte but most of the fatty acids required for TG synthesis are pre-formed in liver and delivered by lipoproteins. 

The discovery in 1929 that some fatty acids required by humans were not synthesised in the... 

Fatty acids require about 7% more oxygen than does carbohydrate to generate the same amount of ATP. Under circumstances where oxygen supply is limiting, for example in parts of the myocardium after an occlusion in one of the arteries, glucose is the preferred fuel and attempts are made to increase blood glucose levels and decrease mobilisation of fatty acids in this condition (see Chapter 22). 

E. Oxidation of odd-cbain fatty acids requires some specialized reactions. 

Oxidation of Unsaturated Fatty Acids Requires Two Additional Reactions... 

Complete Oxidation of Odd-Number Fatty Acids Requires Three Extra Reactions... 

Oxidation of unsaturated fatty acids requires two additional enzymes enoyl-CoA isomerase and 2,4-dienoyl-CoA reductase. Odd-number fatty acids are oxidized by the /3-oxidation pathway to yield acetyl-CoA and a molecule of propionyl-CoA This is carboxylated to methylmalonyl-CoA, which is isomerized to succinyl-CoA in a reaction catalyzed by methylmalonyl-CoA mutase, an enzyme requiring coenzyme B12. 

Desaturation of Fatty Acids Requires a Mixed-Function Oxidase... 

Cuthbertson, W.F.J. 1976. Essential fatty acid requirements in infancy. Am. J. Clin. Nutr. 29, 559-568. 

Holman, R. T., Caster, W. O. and Wiese, H, F. 1964. The essential fatty acid requirement of infants and the assessment of their dietary intake of linoleate by serum fatty acid analysis. Am. J. Clin. Nutr. 14, 70-75. 

A similar situation exists in the case of fatty acid synthesis, which proceeds from acetyl-CoA and reverses fatty acid breakdown. However, both carbon dioxide and ATP, a source of energy, are needed in the synthetic pathway. Furthermore, while oxidation of fatty acids requires NAD+ as one of the oxidants, and generates NADH, the biosynthetic process often requires the related NADPH. These patterns seen in biosynthesis of sugars and fatty acids are typical. Synthetic reactions resemble the catabolic sequences in reverse, but distinct differences are evident. These can usually be related to the requirement for energy and often also to control mechanisms. 

Normally, the method of choice for the analysis of complex mixtures of polyenoic fatty acids such as those derived from fish oils is capillary gas chromatography with prechromato-graphic derivatization and mass spectrometric detection. However, GC is impractical for the purification of the large amounts of polyenoic fatty acids required for biological and clinical studies. Moreover, the temperatures required in GC may cause degradation of oxidized long-chain polyunsaturated fatty acids that are present as minor components of the mixture. 

Kanazawa, A., Teshima, S. and Ono, K. (1979). Relationship between essential fatty acid requirements of aquatic animals and capacity for bioconversion of linolenic acid to highly unsaturated fatty acids. Comparative Biochemistry and Physiology 638,295-301. 

Sinnhuber, R.O., Castell, J.D. and Lee, D.G. (1972). Essential fatty acid requirement of the rainbow trout, Salmo gairdneri. Federation Proceedings 31,1436-1441. 

K Willecke, AB Pardee. Fatty acid-requiring mutant of Bacillus subtilis defective in branched chain a-keto acid dehydrogenase. J Biol Chem 246 5264-5272, 1971. 

Unsaturated fatty acids require the action of additional enzymes in order to be completely degraded by (3-oxidation. 

Oxidation of Unsaturated fatty acids require some additional processing before they can be... 

Bailey JM, Dunbar LM (1973), Essential fatty acid requirements of cells in tissue... 

Fatty acids are utilized as fuels by most tissues, although the brain, red and white blood cells, the retina, and adrenal medulla are important exceptions. Catabolism of fatty acids requires extramitochondrial activation, transport into mitochondria, and then oxidation via the /3-oxidative pathway. The initial step is catalyzed by fatty acyl-CoA synthetase (also called thiokinase and fatty acyl-CoA ligase), as shown in Equation (19.5). The product, fatty acyl-CoA, then exchanges the CoA for carnitine, as shown in Equation (19.6) ... 

Uauy, R. 1990. Are omega-3 fatty acids required for normal eye and brain development in the human J. Ped. Gastroenterol. Nutr. 11, 296-302. 

Very long chain fatty acids are initially oxidized in the peroxisome where the initial oxidation step is catalyzed by acyl-CoA oxidase and the subsequent steps in fS-oxidation are catalyzed by a multi-enzyme complex with hydratase, dehydo-genase, and thiolase activities. Unsaturated fatty acids require additional enzymatic activities, including enoyl-CoA isomerase and dienoyl-CoA reductase. Readers are directed to Vance and Vance (2) for additional details regarding fi-oxidation, including the details of the metabolic reactions. 

Certain Fatty Acids Require Additional Steps for Degradation... 

Epluribus unum. The storage of chemical energy in the form of fatty acids requires carbon building blocks in... 

TABLE 16 Essential Fatty Acid Requirements of Fish d ... 

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