Triacylglycerols analog

L, Spener, F., Hermetter, A. and Pal-TAUF, F. (1996) Inhibition of microbial lipases with stereoisomeric triacylglycerol analog phosphonates. Biochim. Biophys. Acta 1304, 229-244... 

Stadler, P., Kovac, A., Haalck, L., Spener, F. and Paltauf, F. (1995) Stereoselectivity of microbial lipases. The substitution at position sn-2 of triacylglycerol analogs influences the stereoselectivity of different microbial lipases. Eur. J. Biochem. 227, 335-343... 

Duque, M. Graupner, M. Stuetz, H. Wicher, I. Zechner, R. Paltauf, F. Hermetter, A. New fluorogenic triacylglycerol analogs as substrates for the determination and chiral discrimination of Upase activities. J. Lipid Res. 1996,37,868-876. 

The basis for the relationship between bioconcentration and log Kow is the analogy for the partition process between the lipid phase of fish and water and the partition process between n-octanol and water. The reason for using K w arises from the ability of octanol to act as a satisfactory surrogate for lipids in fish tissue. Highly significant relationships between log Kow and the solubility of substances in cod liver oil and triolin exist (Niimi, 1991). Triolin is one of the most abundant triacylglycerols found in freshwater fish lipids (Henderson and Tocher, 1987). 

Generalized structure of a lipoprotein molecule showing the distribution of polar components in an outer shell composed of free cholesterol, phospholipids, and amphipathic proteins and in an inner core composed of neutral triacylglycerols and cholesteryl esters. Phospholipids are oriented with polar head groups toward the aqueous environment and hydrophobic tails toward the neutral core, analogous to their positioning in the outer leaflet of the typical cell membrane. 

Ether analogs of triacylglycerols have been described. l-Alkyl-2,3-diacyl-sn-glycerols are characteristically elevated in tumor lipids and l-alk-l -enyl-2,3-diacyl-sn-glycerols (neutral plasmalogens) have also been detected in tumors, in adipose tissue of mammals, and in fish liver oil. Alkylacetylacylglycerols, RAF precursors, also have been described in human leukemic cells. 

Alkyldiacylglycerols, the 0-alkyI analog of triacylglycerols, are produced by acylation of... 

Thus, the whole process of phenol formation may be considered analogous, in an overall metabolic sense, to fatty acid synthesis in well-fed animals (with the resultant formation and storage of triacylglycerol in adipose tissue) or ketogenesis in the liver of starved or diabetic animals. These situations have effectively adapted to the demands of an imbalanced overproduction of acetyl-CoA. 

The effect of different lipid substrates has a significant impact on the activity of different antioxidants according to their hydrophilic or lipophilic character. For example, a-tocopherol (Figure 9.1) is a lipophilic antioxidant that behaved quite differently in various lipid substrates from its carboxylic acid analog Trolox, which is hydrophilic. In bulk corn oil triacylglycerols, Trolox was a better antioxidant than a-tocopherol, but the opposite trend was observed in... 

The antioxidant activity of ascorbic acid requires the 2-and 3-hydroxyl groups to be unsubstituted. We observed previously that a-tocopherol behaved differently from its carboxylic acid analog, Trolox, in bulk corn oil triacylglycerols compared to the corresponding oil-in-water emulsions. The same behavior is observed when ascorbic acid is compared to ascorbyl palmitate. Although esterification of the 5- or 6-hydroxyl increases the lipid solubility of ascorbic acid, the resulting esters are less active as antioxidants in bulk oil... 

The resolution of several asymmetric triacylglycerols was accomplished using a 25°C Chiracel OD coliram (2 = 210nm). For example, a 200/1 n-hexane/IPA mobile phase almost fully resolved l-eicosapentaenoyl-2,3-dicaprylqyl-sn-glycerol (ECC) fiom its CCE analog. Elution time was 50 min. Similarly, 1-docosahexaenoyl-... 

The reaction of triacylglycerols with alcohol is called alcoholysis. It can be catalysed by acids (sulfuric acid or 4-toluenesulfonic acid), and then an interesterification reaction, which is a parallel reaction to esterification of free fatty acids occurring in the fat. Alcoholysis is kinetically similar to esterification. The base catalysed reaction employs methoxides, hydroxides and carbonates of alkali metals. The most commonly used catalysts are sodium methoxide, sodium hydroxide or potassium hydroxide. Industrially produced alcoholysis products are methyl, ethyl or propyl esters (Figure 3.82) of fatty acids. Analogous to hydrolysis, mixing of fat (oil) with alcohol gives a two-phase system... 

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