Evidence that cholesteryl ester hydrolase and triglyceride lipase are different enzymes in rat liver

James J.S. Chen, Vicki Rothman, Simeon Margolis

Research output: Contribution to journalArticlepeer-review

Abstract

Studies on intracellular cholesteryl ester hydrolase (CEH) and triglyceride lipase (TGL) from rat adipose tissue and adrenal cortex have suggested that a single protein is responsible for both activities. To determine whether one hepatic protein catalyzes both reactions, we studied several properties of CEH and TGL in rat liver. During liver perfusion with heparin, perfusate peaks of TGL and CEH did not consistently coincide, and TGL activity was considerably higher and less heat-stable than that of CEH. Significant TGL, but not CEH, activity was released during incubation of isolated hepatocytes. Although microsomes isolated from hepatocytes contained both activities, the specific activities of CEH and TGL in cytosol from hepatocytes were 95% and 3%, respectively, of those found in cytosol from whole liver. Preincubation of liver cytosol with 5 mM Mg2+ decreased CEH, but not TGL, activity. Intracellular CEH and TGL activities were completely separated by prep-disc gel electrophoresis. Finally, both cytosolic and microsomal TGL, but not CEH, activities were inhibited by antiserum against rat hepatic TGL. We conclude that extracellular TGL does not have CEH activity and intracellular CEH differs from TGL.

Original languageEnglish (US)
Pages (from-to)503-507
Number of pages5
JournalLipids
Volume21
Issue number8
DOIs
StatePublished - Aug 1 1986

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Cell Biology

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