Continuous monitoring of cholesterol oleate hydrolysis by hormone-sensitive lipase and other cholesterol esterases

Journal of Lipid Research

Frédéric Carrière¹  Abdelkarim Abousalham¹  Stefan Petry¹  Günter Muller²  Robert Verger²  Yassine Ben Ali² 

[1] Sanofi Aventis Germany, 65926 Frankfurt am Main, Germany;Enzymology at Interfaces and Physiology of Lipolysis, Unité Propre de Recherche 9025, Centre National de la Recherche Scientifique, 13402 Marseille Cedex 20, France;

关键词: cholesterol ester hydrolase;    triacylglycerol lipase;    cholesterol oleate emulsion;   

DOI  :  

来源: DOAJ

【 摘 要 】

Hormone-sensitive lipase (HSL) contributes importantly to the hydrolysis of cholesteryl ester in steroidogenic tissues, releasing the cholesterol required for adrenal steroidogenesis. HSL has broad substrate specificity, because it hydrolyzes triacylglycerols (TAGs), diacylglycerols, monoacylglycerols, and cholesteryl esters. In this study, we developed a specific cholesterol esterase assay using cholesterol oleate (CO) dispersed in phosphatidylcholine and gum arabic by sonication. To continuously monitor the hydrolysis of CO by HSL, we used the pH-stat technique. For the sake of comparison, the hydrolysis of CO dispersion was also tested using other cholesteryl ester-hydrolyzing enzymes. The specific activities measured on CO were found to be 18, 100, 27, and 3 μmol/min/mg for HSL, cholesterol esterase from Pseudomonas species, Candida rugosa lipase-3, and cholesterol esterase from bovine pancreas, respectively. The activity of HSL on CO is ∼4- to 5-fold higher than on long-chain TAGs. In contrast, with all other enzymes tested, the rates of TAG hydrolysis were higher than those of CO hydrolysis. The relatively higher turnover of HSL on CO observed in vitro adds further molecular insight on the physiological importance of HSL in cholesteryl ester catabolism in vivo.Thus, HSL could be considered more as a cholesteryl ester hydrolase than as a TAG lipase.

【 授权许可】

Unknown