Acylenzyme mechanism and solvent isotope effects for cholesterol esterase-catalyzed hydrolysis of p-nitrophenyl butyrate

Stout, Jay S.; Sutton, Larry D.; Quinn, Daniel M.

doi:10.1016/0005-2760(85)90079-7

Cited by 38 publications

(17 citation statements)

References 10 publications

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“…It was shown by nucleophilic trapping for pNPB as for p-nitrophenyl esters with various acyl chains (31) that hydrolysis is rate-limited by deacylation. An addition of alcohols led to similar increases of V max and K m ; however, at higher concentrations of ethanol (2 M) and n-butanol (0.2 M), respectively, K m increased more rapidly than did V max , and competitive inhibition was assumed (30).…”

Section: Figmentioning

confidence: 98%

“…A nucleophile binding site was postulated to be evident when 4-nitrophenyl acetate was the substrate. Stout et al (30) have investigated the kinetics of the pNPB conversion catalyzed by porcine and bovine pancreatic CEase. It was shown by nucleophilic trapping for pNPB as for p-nitrophenyl esters with various acyl chains (31) that hydrolysis is rate-limited by deacylation.…”

Section: Figmentioning

confidence: 99%

See 1 more Smart Citation

Alternate Substrate Inhibition of Cholesterol Esterase by Thieno[2,3-d][1,3]oxazin-4-ones

Pietsch

Gütschow

2002

Journal of Biological Chemistry

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In a kinetic study, the interaction of bovine pancreatic cholesterol esterase (CEase) with fused 1,3-oxazin-4-ones and 1,3-thiazin-4-ones was investigated, and the compounds were characterized as alternate substrate inhibitors. Inhibition assays were performed in the presence of sodium taurocholate with p-nitrophenyl butyrate as chromogenic substrate. Strong active site-directed inhibition was detected for 2-diethylaminothieno

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Section: Figmentioning

confidence: 98%

Section: Figmentioning

confidence: 99%

Alternate Substrate Inhibition of Cholesterol Esterase by Thieno[2,3-d][1,3]oxazin-4-ones

Pietsch

Gütschow

2002

Journal of Biological Chemistry

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“…The carboxyl ester hydrolytic activity is conferred through a catalytic triad with Ser-HisAsp, forming a charge relay network for substrate hydrolysis. The serine residue at position 194 is responsible for initiating nucleophilic attack on the substrate carboxyl ester bond (12), with histidine-435 participating in an acidbase catalysis reaction on the substrate carbonyl to form an acyl-enzyme intermediate (13)(14)(15). The aspartic acid Abbreviations: CEL, carboxyl ester lipase; lysoPC, lysophosphatidylcholine; PTL, pancreatic triglyceride lipase.…”

Section: Active Sitementioning

confidence: 99%

Carboxyl ester lipase

Hui

Howles

2002

Journal of Lipid Research

196

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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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“…For the three CEases,w ed eterminedv alues of K m in the range of 65-223 mm,w hich are in agreement with reportedM ichaelis constants for the hydrolysis of the related substrate 4-NPB by CEases from different species. [18,[64][65][66][67] However,w ith respect to Figure 2. Range of cholesterol esterase (CEase) concentrations from murine (mCEase, black) and human (hCEase, red) pancreas, in which the enzymatic rate is proportional to the enzymec oncentration.…”

Section: Eukaryoticexpression Of Pancreatic Murineand Human Ceasesmentioning

confidence: 96%

“…Consumption of both substrates followed Michaelis-Menten kinetics and showed smallb ut not negligible nonenzymatic hydrolysis (Figures 3a nd S8), which had to be considered in the following inhibition experiments. [18,[64][65][66][67] However,w ith respect to Figure 2. [18,[64][65][66][67] However,w ith respect to Figure 2.…”

Section: Eukaryoticexpression Of Pancreatic Murineand Human Ceasesmentioning

confidence: 99%

ω‐Phthalimidoalkyl Aryl Ureas as Potent and Selective Inhibitors of Cholesterol Esterase

et al. 2018

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Cholesterol esterase (CEase), a serine hydrolase thought to be involved in atherogenesis and thus coronary heart disease, is considered as a target for inhibitor development. We investigated recombinant human and murine CEases with a new fluorometric assay in a structure-activity relationship study of a small library of ω-phthalimidoalkyl aryl ureas. The urea motif with an attached 3,5-bis(trifluoromethyl)phenyl group and the aromatic character of the ω-phthalimide residue were most important for inhibitory activity. In addition, an alkyl chain composed of three or four methylene groups, connecting the urea and phthalimide moieties, was found to be an optimal spacer for inhibitors. The so-optimized compounds 2 [1-(3,5-bis(trifluoromethyl)phenyl)-3-(3-(1,3-dioxoisoindolin-2-yl)propyl)urea] and 21 [1-(3,5-bis(trifluoromethyl)phenyl)-3-(4-(1,3-dioxoisoindolin-2-yl)butyl)urea] exhibited dissociation constants (K ) of 1-19 μm on the two CEases and showed either a competitive (2 on the human enzyme and 21 on the murine enzyme) or a noncompetitive mode of inhibition. Two related serine hydrolases-monoacylglycerol lipase and fatty acid amide hydrolase-were inhibited by ω-phthalimidoalkyl aryl ureas to a lesser extent.

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Acylenzyme mechanism and solvent isotope effects for cholesterol esterase-catalyzed hydrolysis of p-nitrophenyl butyrate

Cited by 38 publications

References 10 publications

Alternate Substrate Inhibition of Cholesterol Esterase by Thieno[2,3-d][1,3]oxazin-4-ones

Alternate Substrate Inhibition of Cholesterol Esterase by Thieno[2,3-d][1,3]oxazin-4-ones

Carboxyl ester lipase

ω‐Phthalimidoalkyl Aryl Ureas as Potent and Selective Inhibitors of Cholesterol Esterase

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