Purification and properties of human placental acid lipase

Barbara K. Burton*, Howard W. Mueller

*Corresponding author for this work

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Two peaks of lysosomal acid lipase activity were purified from normal human placenta. Acid lipase I, with an estimated molecular weight of 102 500, was purified 1016-fold while acid lipase II, with an estimated molecular weight of 30 600, was purified 3031-fold. The final yields of enzyme activity for acid lipase I and II were 0.9% and 2.2% respectively. The purity of the final preparations was documented by demonstration of a single protein band on polyacryl-amide gel electrophoresis in the presence of sodium dodecyl sulfate. Both preparations of the purified enzyme demonstrated activity towards triolein, cholesteryl oleate and the artificial substrate 4-methylumbelliferyl oleate. Examination of Km values, thermal stability, pH optima, and electrophoretic mobility revealed similar properties for the two enzyme peaks. The response of the two enzyme preparations to inhibitors was similar with both being significantly inhibited by 0.2 M Nad, 0.2 M KC1, 5 mM HgCl2 and 5 mM p-chloromercuribenzoate. The activity of the two preparations as assayed with either triolein or cholesterol oleate was not significantly affected by the addition of bovine serum albumin. In contrast, the 4-methylumbelliferyl oleate activity of both preparations was significantly inhibited by albumin. These findings support the hypothesis that the same enzyme or enzymes are responsible for the intralysosomal hydrolysis of triacylglycerols and cholesterol esters in human tissues.

Original languageEnglish (US)
Pages (from-to)449-460
Number of pages12
JournalBiochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
Volume618
Issue number3
DOIs
StatePublished - Jun 23 1980

Keywords

  • (Human placenta)
  • Acid lipase
  • Cholesterol ester
  • Lysosome
  • Triacylglycerol

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Endocrinology

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