Carboxyl ester lipase

The hydrolysis of zeaxanthin esters by a carboxyl ester lipase indeed enhanced both the incorporation of zeaxanthin in the micellar phase and uptake of zeaxanthin by Caco-2 cells. As mentioned earher, carotenoids can also be linked to proteins by specific bindings in nature and these carotenoid-protein complexes may slow the digestion process and thus make their assimilation by the human body more difficult than the assimilation of free carotenoids. Anthocyanins are usually found in a glycosylated form that can be acetylated and the linked sugars are mostly glucose, galactose, rhamnose, and arabinose. 

Chitchumroonchokchai, C. and Failla, M.L., Hydrolysis of zeaxanthin esters by carboxyl ester lipase during digestion facilitates micellarization and uptake of the xanthophylls by Caco-2 human intestinal cells, J. Nutr., 136, 588, 2006. 

H. Stalder, G. Oesterhelt, B. Borgstrom, Tetrahydrolipstatin Degradation Products Produced by Human Carboxyl-Ester Lipase , Helv. Chim. Acta 1992, 75, 1593-1603. 

The search for intestinal cholesterol transporters extended for many years, beginning with a debate about whether or not it was even a protein-facilitated process (4, 5). The pancreatic enzyme carboxyl ester lipase (CEL, also called cholesterol esterase) was believed to be important to this process (6,7) and several companies devoted considerable resources to the development and testing of compounds to inhibit CEL, with mixed results (8-10). These efforts were abandoned in the mid-1990s, however, after studies with gene-knockout mice demonstrated that the enzyme was important only for absorption of cholesteryl ester (11, 12), which is a minor component of dietary cholesterol and is present at very low levels in bile. Interestingly, CEL is also found in liver where it has been shown to affect HDL metabolism (13). Thus, it may ultimately play an important role in cholesterol metabolism and may yet prove to be a useful drug target for CVD treatment (Camarota and Howies, unpublished). 

Intestinal absorption of dietary cholesteryl ester is decreased but retinyl ester absorption is normal in carboxyl ester lipase knockout mice. Biochemistry 38, 4143-4149. 

Camarota, L. M., Chapman, J. M., Hui, D. Y., and Howies, P. N. (2004) Carboxyl ester lipase coffactionates with scavenger receptor BI in hepatocyte lipid rafts and enhances selective uptake and hydrolysis of cholesteryl esters from HDL3. J. Biol. Chem. 279, 27599-27606. 

While it was previously thought that the lipase of pancreatic origin, the classical lipase, was responsible for the digestion of most dietary fat, it has become clear in recent years that lipolysis in the gastrointestinal rat is a result of the conceited action of four different types of lipases gastric Kpase, classical pancreatic lipase, pancreatic carboxyl ester lipase (identical to cholesterol esterase), and phos-... 

Q. Chen, B. Stemby, B. Akesson, and A. Nilsson. Effects of human poncreftlc lipase-colipase and carboxyl ester lipase on eicosapentamoic and aiachidontc acid ester bonds of triacylglycerols rich in fish oil fatty adds. Biochim. Bbphys. Acta 7044 111(1990). 

M. UndsttOm, B. Stentby, and B. BotgstrtJrn. Conceited notion of human carboxyl ester lipase and pancreatic lipase during lipid digestion In vitro Impair-... 

Howies, P.N., Stemmerman, G.N., Fenoglio Preiser, C.M., Hui, D.Y. 1999. Carboxyl ester lipase activity in milk prevents fat-derived intestinal injury in neonatal mice. Am. J. Physiol. 277, G653-G661. 

Cholesterolesters, esters of vitamins Xenobiotics Carboxyl ester lipase (EC 3.1.1.1) ... 

A. Taylor, J. Zambaux, I. Klisak, T. Mohandas, R. Sparkes, M. Schotz, and A. Lusis. Carboxyl ester lipase a highly polymorphic locus on human chromosome 9 qter. Genomics 10 425 (1991). 

B. Borgstrom, and D. Ameis. cDNA cloning of carboxyl ester lipase from human pancreas reveals a unique proline-rich repeat unit. J. Lipid Res. 32 267 (1991). 

M. Lindstrom, J. Persson, L. Thum, and B. BorgstrOm. Effect of pancreatic phospholipase A2 and gastric lipase on the action of pancreatic carboxyl ester lipase against lipid substrates in vitro. Biochim. Biophys. Acta 1084 194 (1991). 

The bile-salt-dependent lipase of pancreatic juice has many names such as cholesterol esterase, nonspecific lipase, the most rational being carboxyl ester lipase [27], In the case of water-insoluble substrates this enzyme has an absolute requirement for bile salts specifically having hydroxyl groups in the 3a and la positions [28.29]. The best documented role for this enzyme is to allow the absorption of dietary cholesterol, through hydrolysis of cholesterol esters in the lumen. The enzyme also catalyzes the esterification of cholesterol and a role for it has been proposed in cholesterol absorption [30]. In addition, a wide range of primary and secondary fatty acyl esters including glycerides, vitamin A and E esters are hydrolyzed by this enzyme. 

It has been suggested that carboxyl ester lipase has two different bile-salt-binding sites [34-36], one nonspecific for the bile salt structure and one specific for primary bile salts causing the di(poly)merization. An interesting question is whether the bile salts regulate substrate specificity not only by bile salt-enzyme interactions but also by forming the appropriate substrate surface structure [27]. 

Other pancreatic enzymes, like phospholipase A2, amylase, trypsin, chymo-trypsin and liver-esterase, are not blocked by lipstatin. Though, it is known that tetrahydrolipstatin also inhibits other serine-hydrolases such as stomach-lipase and pancreas-carboxylic-ester lipase. [253]... 

Bile salt dependent lipase, also known as carboxyl ester lipase, secreted by acinar cells of the pancreas and associated with LDL in blood, locates with SMC in atherosclerotic lesions and triggers SMC proliferation (434). It may also play a role in lipoprotein metabolism and oxLDL-induced atherosclerosis (reviewed in ref. 435). 

Hui DY, Howies PN. Carboxyl ester lipase structure-function relationship and physiological role in lipoprotein metabolism and atherosclerosis. J Lipid Res2002 43 2017-2030. 

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