Stereospecific triacylglycerol

Straarup, EM Lauritzen, L Faerk, J Hoy, C-E Michaelsen, KF. The Stereospecific Triacylglycerol Structures and Fatty Acid Profiles of Human Milk and Infant Formulas. 

Breckenridge, W. C. 1978. Stereospecific analysis of triacylglycerols. In Handbook of Lipid Research, Vol. I Fatty Acids and Glycerides. A. Kuksis (Editor). Plenum Press, New York pp. 197-232. 

Takagi, T. and Ando, Y. (1995) Stereospecific analysis of monounsaturated triacylglycerols in cocoa... 

The position of fatty acids in the triacylglycerol (TAG) structure not only significantly influences fatty acid absorption, but could provide important markers for establishing the authenticity of different oils. Lawson and Hughes (1988) determined the TAG stereospecific structure of a number of GLA rich oils,... 

Table 4.7 Triacylglycerol stereospecific analysis of evening primrose and borage oils...

Myher, J.J., Kuksis, A., Gehr, K., Park, P.W. and DiersenSchade, D.A. (1996) Stereospecific analysis of triacylglycerols rich in long-chain polyunsaturated fatty acids. Lipids, 31, 207—215. 

Stereospecific analysis of milk fat fractions containing triacylglycerols of different molecular weight have shown that, for fatty acids of chain length C4 to Ci6, the general pattern of fatty acid distribution in normal milk fat is similar to the pattern of distribution in the triacylglycerol fractions of different... 

Figure 1.2. Fischer projection diagram of a triacylglycerol showing the stereospecific numbering (sn-) convention.

Figure 25.4. Proposed fragmentation pathways of triacylglycerol lithium adducts by ESI-MS3. R = fatty acid. Subscripts after R represent the stereospecific locations. (A) Loss of fatty acid at sn-3, then the loss of oc,p-unsaturated fatty acid at sn-2 (Hsu and Turk, 1999). (B) Loss of fatty acid at sn-3, then the loss of C3H40 from glycerol backbone to form acid anhydride. (C) Loss of fatty acid at sn-2, then the loss of C3H40 from glycerol backbone to form acid anhydride.

Most natural triacylglycerols do not have a random distribution of fatty acids on the glycerol backbone. In plant oils, unsaturated acids predominate at the sn-2 position, with more saturated acids at sn-l and sn-3. The distribution of fatty acids at the sn-l and sn-3 positions is often similar, although not identical. However, a random distribution between these two positions is often assumed as full stereospecific analysis is a time-consuming specialist procedure. In animal fats, the type of fatty acid predominating at the sn-2 position is more variable for example, palmitate may be selectively incorporated as well as unsaturated acids (Table 5). 

Figure 1. A triacylglycerol molecule (R fatty acid moiety, sn stereospecific number).

Harp and Hammond (45) explored the stereospecific distribution of acyl groups on the three positions of the glycerol molecule for soybean triacylglycerols with a wide range in fatty acid composition. They found that the amount of an acyl group... 

EFFECTS OF STEREOSPECIFIC STRUCTURE OF DIETARY TRIACYLGLYCEROLS ON THEIR HEALTH-RELATED NUTRITIONAL EFFECTS... 

On the other hand, the specificities of hPL and RmL are very low. RmL strongly favors positions 1 and 3 (rather independent of the type of the fatty acid) in triacylglycerols. To date it is the only lipase that has been crystallized in a complex with an inhibitor containing a short aliphatic chain (Brzozowski et al., 1991). However, the low resolution of the study does not allow for a detailed description of the molecular basis of substrate specificity. Also, no structure-based analysis of stereospecificity in lipases is possible results of purely chemical studies (Kaz-lauskas et al., 1991, and references therein Xie et al., 1990) fall outside the scope of this review. 

Triacylglycerols (TAG) are the primary neutral lipids in soybean oil. Due to the high concentration of unsaturated fatty acid in soybean oil, nearly all the TAG molecules contain at least two unsaturated fatty acids, and di- and trisaturates are essentially absent (List el al. 1977). In natural oils and fats, the fatty acids are not usually randomly distributed among the three hydroxyl groups of glycerol but are associated in particular patterns. Several theories of regiospecific distribution exist (Litchfield 1972), but the 1,3-random, 2-random theory is most widely accepted. The stereospecific distribution of fatty acyl groups in soybean oils... 

Table 8.4 Stereospecific analyses of triacylglycerols from three peanut varieties...

Santinelli, F., Damiani, R and Christie, W.W. (1992) The triacylglycerol structure of olive oil determined by silver ion high performance liquid chromatography in combination with stereospecific analysis. J. Am. Oil Chem. Soc., 69, 552-557. 

Harp, T.K. E.G. Hammond. Stereospecific analysis of soybean triacylglycerols. Lipids 1998, 33, 209-216. 

Sallustio, B.C. Meffin, P.J. Knights, K.M. The stereospecific incorporation of fenoprofen into rat hepatocyte and adipocyte triacylglycerols. Biochem. Pharmacol. 1988, 37, 1919-1923. 

Karupaiah, T. and Sundram, K. (2007). Effects of stereospecific positioning of fatty acids in triacylglycerol structures in native and randomized fats a review of their nutritional implications. Nutrition Metabolism, 4,16. 

Procedures for pancreatic lipase use are described by Jensen and Pitas (1976) and for lipoprotein, lingual and hepatic lipases by Paltauf et al, (1974). Stereospecific analysis of fatty acids in triacylglycerols has been fully discussed by Brecken-ridge (1978). 

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