Fatty acids allenic

Allene oxide synthase route. Allene oxide synthase dehydrates hydroperoxides, affording allene oxide fatty acids, Allene oxides are rapidly hydrolyzed into ketols [2,6]. Allene oxide, corresponding to 13-HPOT, along with hydrolysis undergoes cyclization, affording cyclopentenone 12-oxo-10,15(Z)-phytodienoic acid. The last upon its reduction and j8-oxidation is converted into jasmonic acid ... 

Peroxidation of lipids is another factor which must be considered in the safety evaluation of liposome administration. Smith and coworkers (1983) demonstrated that lipid peroxides can play an important role in liver toxicity. Allen et al. (1984) showed that liposomes protected by an antioxidant caused less MPS impairment than liposomes subjected to mild oxidizing conditions. From the study of Kunimoto et al. (1981) it can be concluded that the level of peroxidation in freshly prepared liposome preparations and those on storage strongly depends both on the phospholipid fatty acid composition and on the head group of the phospholipid. Addition of appropriate antioxidants to liposomes composed of lipids which are liable to peroxidation and designed for use in human studies is therefore necessary. 

Kennedy, M.W., Allen, J.E., Wright, A.S., McCruden, A.B. and Cooper, A. (1995a) The gpl5/400 polyprotein antigen of Brugia malayi binds fatty acid and retinoids. Molecular and Biochemical Parasitology 71, 41-50. 

Allen and DuBois136 have calculated that the R. Q. of 0.707, obtainable when fat is completely oxidized, would be lowered to 0.669 if the /3-hydroxybutyric acid were not metabolized. If more than one molecule of the ketone bodies is produced from one molecule of the fatty acid, as has been suggested,83 the R. Q. would be further lowered. This may be further complicated by a resulting upset in acid-base balance. 

SONG, W.C., FUNK, C.D., BRASH, A.R., Molecular cloning of an allene oxide synthase A cytochrome P450 specialized for the metabolism of fatty acid hydroperoxides, Proc. Natl. Acad. Sci. USA, 1993, 90, 8519-8523. 

In milk with a normal pH of 6.7, most of the acids are in the salt form and have much less flavor than if they were completely in the acid form (Kuzdzal-Savoie, 1980). In fact, acidification of milk greatly enhances the sensitivity of organoleptic detection of lipolysis in milk (Tuckey and Stad-houders, 1967). The detection of rancidity is reduced by the association of the FFAs with certain proteins in milk (Parks and Allen, 1979 Keenan et al., 1982) and by heating of milk (Kintner and Day, 1965). The phase in which the fatty acids are soluble also influences their flavor threshold, since the short-chain acids have much lower thresholds in fat than in water, while the opposite applies to the long-chain acids (Patton, 1964). For example, butyric acid (C o) has a flavor threshold of 7 mg/kg in water, but only of 0.6 mg/kg in oil (Delahunty and Piggott, 1995). 

Parks, O.W., Allen, C. 1979. State of unesterified fatty acids in skim-milk. J. Dairy Sci. 62, 1045-1050. 

FROELICH, J.E., ITOH, A., HOWE, G.A., Tomato allene oxide synthase and fatty acid hydroperoxide lyase, two cytochrome P450s involved in oxylipin metabolism, are targeted to different membranes of chloroplast envelope., Plant Physiol., 2001,125,306-317. 

Allen, C. A. W., Watts, K. C., Ackman, R. G., and Pegg, M. J. 1999. Predicting the Viscosity of Biodiesel Fuels from Their Fatty Acid Ester Composition. Fuel, 78, 1319-1326. 

JAs are derived from linolenic acid via an octadecanoid pathway consisting of several enzymatic steps (Figure 36). Multiple compartments in plant cells participate in JA synthesis. The early steps of this pathway occur in chloroplasts, where linolenic acid is converted to OPDA by means of the three enzymes lipoxygenase (LOX), allene oxide synthase (AOS), and allene oxide cyclase (AOC).867-869 Linolenic acid is oxygenated by 13-LOX producing a peroxidized fatty acid 13-hydroperoxylinolenic acid. The product is subsequently metabolized by AOS to an unstable compound allene oxide. Allene oxide is sequentially converted by AOC to produce OPDA. An alternative pathway from another trienoic fatty acid, hexadecatrienoic acid (16 3), is present in chloroplasts.870 In this pathway, dinor OPDA is produced instead of OPDA. OPDA and dinor OPDA are transported into the peroxisome. An ABC transporter involved in this transport was identified in... 

Figure 2.26. Adsorption of fatty acids from heptane on haematite (a-Fe20g) Ag (BET (Njl) = 3.45 g". Temperature not stated. Data by Allen and Patel, loc. clt.,...

The first successful preparation of phosphorus-containing heterocyclic fatty acid derivatives has been presented. Reaction of cx-keto allene (379) with trimethyl phosphite gave oxaphosphole derivative (380). Similar transformations with a-keto and a-chloro-ot-ketoallenes (381) and (382) led to the formation of alkenylphosphonates (383) and (384), respectively (Figure 64) ... 

If the biosynthesis proceeds via a domino-cyclization, it would require a novel transformation, because the known reactions are not able to create such unfavored ring systems as that of 1. A possible substrate for a thermodynamically favorable reductive polycyclization with addition of 2 H atoms would be the allenic C2o-fatty acid 9,10,12,16,18,19-docosahexanoic acid (32). ... 

Allen A, Padley GH, Whalley GR. Fatty acid composition of some soapmaking fats and oils. Part 4 groundnut (peanut oil). Soap Perfum Cosmet 1969 42 725-726. 

Rayasam GV, Tulasi VK, Davis JA, Bansal VS (2007) Fatty acid receptors as new therapeutic targets for diabetes. Expert Opin Ther Targets 11 661-671 Ren Y, Silverstein RL, Allen J, Savill J (1995) CD36 gene transfer confers capacity for phagocytosis of cells undergoing apoptosis. J Exp Med 181 1857-1862 Rolls ET (2007) Sensory processing in the brain related to the control of food intake. Proc Nutr Soc 66 96-112... 

Higher Fatty Acids. Oxidation of higher paraffins can give mixtures of acids, alcohols, and carbonyl compounds, although fatty acids may be obtained as the principal product. Publications by Wittka (126), Stossel (111), Allen (3), Lanning (62), Zabel (128), and Gall (35) are of importance in this field. 

Allen, D., Cocks, L. V., and Sutcliffe, H. T., Production of Synthetic Fatty Acids and Their... 

Hankenson KD. Watkins BA. Schoenlein lA, Allen KG. Turek JJ. Omega-3 fatty acids enhance ligament fibroblast collagen formation in association with changes in interleukin-6 production. Proc Soc Exp Biol Med 2000 223 88-95. 

Rothman D, Allen H, Herzog L, Pilapil A, Seiler CM, Zurier RB. Effects of unsaturated fatty acids on interleukin-1 beta production by human monocytes. Cytokine 1997 9 1008-1012. 

Fig. 8. Metabolism of 18 3 fatty acid to oxylipins. I. Lipoxygenase 2, alleneoxide synthase 3, allene oxide cyclase 4, 12-oxo-phytodienoic acid reductase, -oxidation 5, hydroperoxide lyase.

In some instances certain stationary phases can also be used as efficient reagents for subtraction. Thus, for instance, according to Allen [76], FFAP (free fatty acid) subtracts aldehydes, Bierl et al. [65] showed that this stationary phase removes epoxides selectively. Aldehydes that have a substituent in the a-position are only 80% removed. The retention mechanism is not clear. It should be noted that according to Cronin [77], FFAP sometimes yields unsatisfactory results. 

When, however, 13(S)-HPOD was incubated with an ammonium sulphate precipitate of defatted com germ, the resulting 12-oxo-PDA was not optically pure but a mixture of enantiomers in a ratio of 82.18 [35]. The 12-oxo-PDA obtained by incubation of 13(S)-HPOT with flaxseed extracts was found to be a racemic mixture [36]. These results may be due to low or absent allene oxide cyclase activity in the preparations used [34]. The allene oxide cyclase, a novel enzyme in the metabolism of oxygenated fatty acids was partially characterised and found to be a soluble protein with an apparent molecular weight of about 45 kDa which catalysed specifically the conversion of allene oxide into 12-oxo-PDA [34]. The allene oxide was very unstable and was rapidly hydrolysed in aqueous media into stable 12-oxo-13-hydroxy-9(z),15(z)-octadecadienoic acid (a-ketols) [34]. 

Howe, G.A., G.I. Lee, A. Itoh, L. Li, and A.E. DeRocher (2000). Cytochrome P450-depend-ent metabolism of oxylipids in tomato. Cloning and expression of allene oxide synthase and fatty acid hydroperoxide lyase. Plant Physiol. 123, 711-724. 

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