Bile salt‐stimulated lipase in human milk and carboxyl ester hydrolase in pancreatic juice

Bläckberg, Lars; Lagadic‐Gossmann, Dominique; Hernell, Olle; Guy, Odette; Olivecrona, Thomas

doi:10.1016/0014-5793(81)80636-9

Cited by 110 publications

(40 citation statements)

References 21 publications

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“…The presence of BSDL in such a wide range of tissues and organs, normal or pathological, suggests a broad physiological function in the body. The underlying question about the physiological function of BSDL outside the duodenum concerns the activation of the enzyme, which in the absence of bile salt cannot hydrolyze lipid substrates (2,39). We, therefore, have extended the effect of anionic bile salts to acidic phospholipids that have been shown to regulate neutral cholesterol esterase of alveolar macrophages (14).…”

Section: Discussionmentioning

confidence: 99%

Site-directed Mutagenesis of the Basic N-terminal Cluster of Pancreatic Bile Salt-dependent Lipase

Aubert¹,

Sbarra

Petit-Thévenin

et al. 2002

Journal of Biological Chemistry

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Previous studies have postulated the presence of a heparin-binding site on the bile salt-dependent lipase (BSDL), whereas two bile salt-binding sites regulate the enzyme activity. One of these sites may overlap with the tentative heparin-binding site at the level of an N-terminal basic cluster consisting of positive residues Lys 32 , Lys 56 , Lys 61 , Lys 62 , and Arg 63 . The present study uses specific site-directed mutagenesis to determine the functional significance of this basic cluster. Mutations in this sequence resulted in recombinant enzymes that were able to bind to immobilized and to cell-associated heparin before moving throughout intestinal cells. Recombinant BSDL was fully active on soluble substrate, but mutants were less active on micellar cholesteryl oleate in comparison with the wild-type enzyme. Activation studies by primary (sodium taurocholate) and by secondary (sodium taurodeoxycholate) bile salts revealed that the activation of BSDL by sodium taurocholate at concentrations below the critical micellar concentration, and not that evoked by micellar bile salts, was affected by substitutions, suggesting that this Nterminal basic cluster likely represents the specific bile salt-binding site of BSDL. Substitutions also affected the activation of the enzyme promoted by anionic phospholipids, extending the function of this site to that of a cationic regulatory site susceptible to accommodate anionic ligands.

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Section: Discussionmentioning

confidence: 99%

Site-directed Mutagenesis of the Basic N-terminal Cluster of Pancreatic Bile Salt-dependent Lipase

Aubert¹,

Sbarra

Petit-Thévenin

et al. 2002

Journal of Biological Chemistry

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“…For the human neonate, whose pancreas is not functional [22], the enzyme involved in lipid hydrolysis is provided by the mother's milk [23]. This enzyme, the bile-salt-stimulated lipase, is similar if not identical to the pancreatic carboxylic-ester hydrolase [24]. The origin of the specificity of the activation by bile salts may lie in the fact that only primary bile salts are present in the bile of neonate.…”

Section: Discussionmentioning

confidence: 99%

On the Probable Involvement of Arginine Residues in the Bile‐Salt‐Binding Site of Human Pancreatic Carboxylic Ester Hydrolase

Lagadic‐Gossmann¹,

Campése²,

Multigner³

et al. 1983

European Journal of Biochemistry

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Modification of arginine residues with 2,3-butanedione inhibits the carboxylic-ester hydrolase activity on soluble and emulsified substrates when assayed with bile salts. The a-dicarbonyl reagent modifies seven of the nineteen arginine residues present per enzyme molecule. Nevertheless the inactivation with butanedione is greatly diminished when the protein is in the presence of negatively charged micellar bile salt. In these conditions we observe the protection of one arginine residue by sodium taurodeoxycholate and of two arginine residues by sodium cholate. This suggests that the carboxylic-ester hydrolase from human pancreatic juice contains at least two arginine residues essential for the activation by bile salts. All our data confirm the presence of two bile-salt-binding sites on the enzyme in which one arginine per site is involved and plays the general role of an anionic binding site. This study provides evidence that arginine residues may play an essential role in the interaction between bile salts and protein.For many years the distinction between the pancreatic carboxylic-ester hydrolase and the pancreatic cholesterol-ester hydrolase was based not only on the substrate specificity but also on the bile-salt effect. While carboxylic-ester hydrolases are activated by all bile salts, cholesterol-ester hydrolases are only activated by primary bile salts [I, 21. In a recent study we have demonstrated that the pancreatic activities on soluble carboxylic esters and on cholesteryl esters were due, at least in the human pancreatic juice, to a single enzyme. This enzyme seems also to be responsible for the lipid-soluble-vitaminsesters hydrolase, non-specific lipase and lysophospholipase activities of human pancreatic juice [3, 41. Because of its large specificity we have called this enzyme carboxylic-ester hydrolase.We have recently postulated the presence of two bile-saltbinding sites on the human pancreatic carboxylic-ester hydrolase [3]. One of these, (site SP in Fig. 1) would be specific for the 3a and 7a-hydroxylated positions of cholanic acid (primary bile salts). It would promote the dimerization and consequently the activity of the enzyme on hydrophobic substrate (CE) after bile-salt solubilization. The second site (site U, Fig. 1) would be non-specific for the hydroxyl positions of bile salts and would be located at (or near) the active center (site C, Fig. 1) of the carboxylic-ester hydrolase. This enzyme shows a poor activity on water-soluble substrates. Nevertheless, the interaction of bile salts, primary or secondary with the unspecific site, U, gives a more effective enzyme [I, 51 probably by inducing a modification in the active site of the enzyme. Interestingly, in a recent paper it has been suggested [6] that the phospholipase A2 from cobra venom has two kinds of functional sites: an activator site and a catalytic site, showing some analogy with the pancreatic carboxylic-ester hydrolase. From the scheme presented in This work has been carried out in an attempt to answer these questions, at least...

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“…The hydrolysis of water-insoluble substrates by CEL requires bile salt containing 3 ␣ ,7 ␣ -hydroxy groups (e.g., cholate or chenodeoxycholate and their conjugates) (24). Chemical modification studies showed that arginine residues in CEL are important for its interaction with bile salt (25,26).…”

Section: Bile Salt Bindingmentioning

confidence: 99%

Carboxyl ester lipase

Hui

Howles

2002

Journal of Lipid Research

191

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Carboxyl ester lipase (CEL), previously named cholesterol esterase or bile salt-stimulated (or dependent) lipase, is a lipolytic enzyme capable of hydrolyzing cholesteryl esters, tri-, di-, and mono-acylglycerols, phospholipids, lysophospholipids, and ceramide. The active site catalytic triad of serine-histidine-aspartate is centrally located within the enzyme structure and is partially covered by a surface loop. The carboxyl terminus of the protein regulates enzymatic activity by forming hydrogen bonds with the surface loop to partially shield the active site. Bile salt binding to the loop domain frees the active site for accessibility by water-insoluble substrates. CEL is synthesized primarily in the pancreas and lactating mammary gland, but the enzyme is also expressed in liver, macrophages, and in the vessel wall. In the gastrointestinal tract, CEL serves as a compensatory protein to other lipolytic enzymes for complete digestion and absorption of lipid nutrients. Importantly, CEL also participates in chylomicron assembly and secretion, in a mechanism mediated through its ceramide hydrolytic activity. Cell culture studies suggest a role for CEL in lipoprotein metabolism and oxidized LDL-induced atherosclerosis. Thus, this enzyme, which has a wide substrate reactivity and diffuse anatomic distribution, may have multiple functions in lipid and lipoprotein metabolism, and atherosclerosis. Carboxyl ester lipase (CEL), previously named pancreatic cholesterol esterase and also known as bile salt-stimulated (or -dependent) lipase, is a nonspecific lipolytic enzyme capable of hydrolyzing cholesteryl esters, tri-, di-, and mono-acylglycerols, phospholipids, lysophospholipids, and ceramide (1-3). The hydrolysis of water-insoluble carboxyl esters with long chain fatty acyl groups by CEL requires its activation by bile salt. However, CEL hydrolysis of water-soluble substrates such as carboxyl esters with short chain fatty acids or lysophospholipids does not have an absolute dependence on bile salt activation. The CEL protein is synthesized primarily in the pancreatic acinar cells and lactating mammary glands of higher mammals. Small amounts of CEL are found in other tissues, particularly the liver, macrophages, endothelial cells, and eosinophils (4-10). Extensive research has been performed in recent years on the structure-function relationship of this protein as well as its physiological role in lipid metabolism. A significant body of work has also been devoted to studying CEL processing and transport in pancreatic acinar cells. The latter topic was reviewed recently (11) and will be discussed only briefly in this article when appropriate. This article will present an updated review on the structure-function studies of CEL as well as an in-depth discussion on the current understanding of its role in lipid metabolism. PROTEIN STRUCTURE-FUNCTION RELATIONSHIP Active siteThe nucleotide sequence of CEL from various species shows that it is a highly conserved protein belonging to the ␣ / ␤ hydrolase family. The carb...

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Bile salt‐stimulated lipase in human milk and carboxyl ester hydrolase in pancreatic juice

Cited by 110 publications

References 21 publications

Site-directed Mutagenesis of the Basic N-terminal Cluster of Pancreatic Bile Salt-dependent Lipase

Site-directed Mutagenesis of the Basic N-terminal Cluster of Pancreatic Bile Salt-dependent Lipase

On the Probable Involvement of Arginine Residues in the Bile‐Salt‐Binding Site of Human Pancreatic Carboxylic Ester Hydrolase

Carboxyl ester lipase

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