2-Monoacylglycerol

FIGURE 24.3 (a) A duct at the junction of the pancreas and duodenum secretes pancreatic juice into the duodenum, the first portion of the small intestine, (b) Hydrolysis of triacylglycerols by pancreatic and intestinal lipases. Pancreatic lipases cleave fatty acids at the C-1 and C-3 positions. Resulting monoacylglycerols with fatty acids at C-2 are hydrolyzed by intestinal lipases. Fatty acids and monoacylglycerols are absorbed through the intestinal wall and assembled into lipoprotein aggregates termed chylomicrons (discussed in Chapter 25). 

Lipids in the diet (Figure 15-6) are mainly triacyl-glycerol and are hydrolyzed to monoacylglycerols and fatty acids in the gut, then reesterified in the intestinal... 

Figure 15-6. Transport and fate of major lipid substrates and metabolites. (FFA, free fatty acids LPL, lipoprotein lipase MG, monoacylglycerol TG, triacylglycerol VLDL, very low density lipoprotein.)...

Figure 24-2. Biosynthesis of triaq/lglycerol and phospholipids. ( , Monoacylglycerol pathway (D, glycerol phosphate pathway.) Phosphatidylethanolamine may be formed from ethanolamine by a pathway similar to that shown for the formation of phosphatidylcholine from choline.

Monoacylglycerols are the monoesters of glycerol that consist of only one fatty acid attached either to the position 1(3) or 2 of the glycerol backbone. However, because both diacylglycerols and monoacylglycerols are hydrolytic products of triacylglycer-ols and phospholipids, they may be present, if any, only in negligible levels in animal and plant tissues. 

Monoacylglycerol in butter oil can be detected under UV fight or with iodine vapor, and the detected bands extracted with hexane isopropanol (3 2) can be used... 

Anandamide amidase recognizes and hydrolyzes 2-AG (Goparaju, 1999 Di Marzo, 1999 Lang, 1999) however, there is evidence for the existence of another specific hydrolase [monoacylglycerol (MAG) lipase] that hydrolyzes 2-AG (D. Piomelli and A. Makriyannis, 2000, personal communication). In addition to this pathway, 2-AG diffuses rapidly into the cell membrane where it could be either hydrolyzed to arachidonic acid and glycerol or esterified back to phosphoglycerides (Di Marzo, 1999b). 

Moorhouse KG, Logan CJ, Hutson DH, Dodds PF (1990) The incorporation of 3-phenoxybenzoic acid and other xenobiotics acids into xenobiotic lipids by enzymes of the monoacylglycerol pathway in microsomes from adult and neonatal tissues. Biochem Pharmacol 39 1529-1536... 

Monoacylglycerols, 10 802, 804, 822 Monoalkanolamine titanates, 25 95 Monoalkoxytriacyl titanates, 25 129 Monoalkylamines, 13 105 Monoalkylboranes, 13 632, 633, 635 Monoalkylhydrazines, 13 571 Monoalkyl phosphate extractants,... 

Diacylglycerols Monoacylglycerols Cerebrosides Glycosyl diacylglycerols Sulpholipids... 

Various combinations of hexane or light petroleum (40-60°C, bp) and diethyl ether, usually with a small amount of acetic acid (e.g. 90 10 1) or diisopropyl ether and acetic acid (98.5 1.5) are commonly used. The greater mobility is demonstrated by cholesterol esters followed by triacylglycerols, free fatty acids, cholestorol, diacylglycerols and monoacylglycerols, with complex polar lipids remaining unmoved. Double development in two solvents, e.g. diisopropyl... 

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