Acyl Glycerol

Figure 1. Structure of liposomes and lipid microsphere a), multilamellar vesicle b). unilamellar vesicle c). lipid microsphere. Symbols inside the microsphere indicate di- and tri-acyl glycerol.

DAGKa Di acyl glycerol kinase accessory domain (presumed) E(MP) 0(0) 7(7) ... 

More complex structures, often related to natural products are prepared by organic synthesis. Among them can be mentioned (f )-3-hydroxytetradecanoic acid (the double-tail hydrophobic moiety of lipid A), sphingosine derivatives related to the ceramides or 1,2- and l,3-dialkyl(acyl)glycerols related to glyco-glycerolipids, glycerophospholipids, and GPI anchors of membrane proteins. The preparations of the above derivatives were reported several years ago but some improvements have been published more recently. 

We will use a shorthand designation for fatty acids, i.e., 18 0, stearic acid 18 1, oleic acid etc. The first figure is the number of carbons, the second the number of double bonds. To locate the fatty acids in acyl-glycerols, stereospecific numbering (sn) will be employed. If a glycerol molecule is drawn with the secondary hydroxyl to the left, the hydroxyl above is sn-1 and that below is sn-3. 

Lecithins and related phospholipids usually contain a saturated fatty acid in the C-l position but an unsaturated acid, which may contain from one to four double bonds, at C-2. Arachidonic acid is often present here. Hydrolysis of the ester linkage at C-2 yields a l-acyl-3-phosphoglycerol, better known as a Iysophosphatidylcholine. The name comes from the powerful detergent action of these substances which leads to lysis of cells. Some snake venoms contain phospholipases that form Iysophosphatidylcholine. Lysophosphatidic acid (l-acyl-glycerol-3-phosphate) is both an intermediate in phospholipid biosynthesis (Chapter 21) and also a signaling molecule released into the bloodstream by activated platelets.15... 

XXII) Gu ai acyl glycerol 0-coniferyl ether R---------CH2OH... 

The method can be applied for saturated fatty acids, unsaturated fatty acids, fatty esters, fatty alcohols and acyl-glycerols. The regression is based on 1200 data points. The absolute deviation in predicting vapor pressure is 6.82%. Another advantage of Eq. (14.1) is the capability of predicting the VLE of mixtures of fatty acids and esters by using the UNIFAC model for liquid activity. The comparison with experimental data shows good accuracy not achieved by other methods [40]. 

Fatty acyl- Glycerol Step 1 Phosphatidic CoA + 3-phosphate acid... 

At 24 MPa, the calculated amount extracted was 54.4% of the available lipid versus 45% for the experimental amount. At 31 MPa, the values were 58% and 42%. Lee et al. (7) indicated that 57% of the total lipid composition in Skeletonema costatum consisted of acyl glycerols. The calculated yields of 58% and 54% in the present study indicated that almost all of the nonpolar lipids were extracted by CO,. Friedrich et al. (14) claimed that no significant difference was observed in the quantity of total saponiflables between SC CO2 and hexane extracted soybean oils. This is in agreement with the results for SC CO2 extracted and solvent extracted oils of Skeletonema. 

Synthesis of 2-monoglycerides. Boric acid is recommended for removal of the 1,3-benzylidene group from l,3-benzyUdene-2-acyl glycerols. The derivative is heated in triethyl borate with finely powdered boric acid until conversion to the diborate ester is complete and this is then hydrolyzed with water, for example to 2-monoolein. 

CTP phosphocholine cytidylyltransferase (3) glycerol kinase (4) acyl-CoA glycerol-3-phosphate acyltransferase (5) acyl-CoA acyl glycerol-3-phosphate acyltransferase (6) phosphatidic acid phosphatase (7) CDP-choline diacylglycerol phosphocholine transferase. 

Fig. 3. Major biosynthetic pathways and enzymes for the endocannabinoid 2-arachidonoyl-glycerol (2-AG). DAG, di-acyl-glycerol lipase PA, phosphatidic acid PI, phosphoinositide PLC, phospholipase C. P represents a phosphate group...

The effect of phloretin on the dipole potential of lipids with different head groups suggests that the surface properties may be modulated by the group esterified to the phospho acyl glycerol moiety. 

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