In vitro stereoselective hydrolysis of diacylglycerols by hormone-sensitive lipase

Biochim Biophys Acta. 2010 Jan;1801(1):77-83. doi: 10.1016/j.bbalip.2009.09.020. Epub 2009 Oct 1.

Abstract

Hormone-sensitive lipase (HSL) contributes importantly to the mobilization of fatty acids in adipocytes and shows a substrate preference for the diacylglycerols (DAGs) originating from triacylglycerols. To determine whether HSL shows any stereopreference during the hydrolysis of diacylglycerols, racemic 1,2(2,3)-sn-diolein was used as a substrate and the enantiomeric excess (ee%) of residual 1,2-sn-diolein over 2,3-sn-diolein was measured as a function of DAG hydrolysis. Enantiomeric DAGs were separated by performing chiral-stationary-phase HPLC after direct derivatization from lipolysis product extracts. The fact that the ee% of 1,2-sn-diolein over 2,3-sn-diolein increased with the level of hydrolysis indicated that HSL has a preference for 2,3-sn-diolein as a substrate and therefore a stereopreference for the sn-3 position of dioleoylglycerol. The ee% of 1,2-sn-diolein reached a maximum value of 36% at 42% hydrolysis. Among the various mammalian lipases tested so far, HSL is the only lipolytic carboxylester hydrolase found to have a pronounced stereospecificity for the sn-3 position of dioleoylglycerol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diglycerides / chemistry
  • Diglycerides / metabolism*
  • Humans
  • Hydrolysis
  • Kinetics
  • Lipolysis
  • Stereoisomerism
  • Sterol Esterase / chemistry
  • Sterol Esterase / metabolism*
  • Substrate Specificity

Substances

  • Diglycerides
  • Sterol Esterase
  • diolein