Monoacylglycerols, structure

The composition and structure of bovine milk fat have been reviewed extensively. There are early reviews by Morrison (1970), Christie (1978, 1995), Jensen and Clark (1988), and Jensen and Newberg (1995) recent articles include a comprehensive review of recent research by Jensen (2002) and two book chapters by Vanhoutte and Huyghebaert (2003), and Zegarska (2003). Bovine milk lipids are similar to the milk lipids of other species as they are largely composed of triacylglycerols however, there are also minor amounts of diacyl-glycerols, monoacylglycerols, free (unesterified) fatty acids, phospholipids and... 

Properties of Component Phases The composition and physicochemical properties of both the oil and aqueous phases influence the size of the droplets produced during homogenization (52). Variations in the type of oil or aqueous phase will alter the viscosity ratio, ri ,/ri(-, which determines the minimum size that can be produced under steady-state conditions. The interfacial tension of the oil-water interface depends on the chemical characteristics of the lipid phase, e.g., molecular structure or presence of surface-active impurities, such as free fatty acids, monoacylglycerols, or diacylglycerols. These surface-active hpid components tend to accumulate at the oil-water interface and lower the interfacial tension, thus lowering the amount of energy required to disrupt a droplet. 

Tjiong, H.B. Debuch H. Lysosomal bis (monoacylglycerol)phosphate of Rat Liver, Its Induction by Chloroquine and Its Structure. Hoppe-Seyler s Physil. Chem. 359, 71-79 (1978). 

It should be pointed out that the comparable hydrolysis rate for amide and ester bonds has a biological meaning FAAH must bind and hydrolyze its FAA substrates against a background of a large excess of structurally related esters such as monoacylglycerols (Mechoulam et al., 1995). To reach this goal, the... 

Lee et al. demonstrated the synthesis of nanostructured cubic polymer gels by copolymerization of dienyl substituted lipids [66]. No phase transitions, or changes in dimensions, were observed with temperature changes for the polymerized sample. Furthermore, the polydomain square lattice of the gel was visualized by TEM of ultramicrotomed samples after extraction of the template (Fig. 7). In contrast, copolymerization of monoacylglycerol and 1,2-diacylglyc-erol in a cubic lyotropic state did not result in a continuous gel structure. Linear polymer chains were obtained instead, and the cubic morphology was destroyed by addition of organic solvent [67]. Similar polymerizations in the inverted... 

Fig. 1. Structures of lipids covalently attached to proteins. Panel A shows proteins that are lipidated on cytoplasmi-cally exposed amino acids, whereas panel B shows lipidated proteins in the extracellular leaflet. (A) iV-myristoyl glycine, palmitate thioester-linked to cysteine, farnesyl, or geranylgeranyl (prenyl) thioether-linked to cysteine. (B) A/-palmitoyl cysteine, cholesterol ester-linked to glycine, and a minimal GPI anchor linked to the to amino acid in a GPI-anchored protein. The GPI structure is shown with a diacylglycerol moiety containing two ester-linked fatty acids. Other GPI anchors are based on ceramide, while yet others have monoacylglycerol, a fatty acid ether-linked to glycerol, and/or a fatty acid ester-linked to inositol.

Two PLAs have been purified from Escherichia coli based on their differential sensitivity to treatment with detergents [2]. A detergent-insensitive enzyme is localized in the outer membrane, whereas a detergent-sensitive enzyme is found on the cytoplasmic membrane and in soluble fractions. The outer membrane enzyme, known as outer membrane phospholipase A, has broad substrate specificity and demonstrates PLA, PLAj, lysophospholipase A, and lysophospholipase Aj activity as well as activity for hydrolyzing monoacylglycerols and diacylglycerols. The crystal structure allows a more detailed discussion of an integral membrane phospholipase [12]. 

Irimescu, R, Furihata, K, Hata, K, Iwasato, Y and Yamane, T (2001) Two-step enzymatic synthesis of docosahexaenoic acid-rich symmetrically structured triacylglycerols via 2-monoacylglycerols. J. Am. Oil Chem. Soc., 78, 743-748. 

During the process of absorption, cholesterol dissolved in the lipid core of micelles is transported from the lumen of the small intestine across the intestinal wall and into the lymph. Because the solubility of cholesterol in aqueous systems is low, its absorption depends on the formation of detergent structures (mixed micelles) in the small intestine. These are composed mainly of bile salts, phospholipids, digestion products of fats such as fatty acids and monoacylglycerols, cholesterol (of which 90% is in free form), and fat-soluble micronutrients (Figure 6). 

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