Purified human serum PON1 does not protect LDL against oxidation in the in vitro assays initiated with copper or AAPH

John F. Teiber, Dragomir I. Draganov, Bert N. La Du

Research output: Contribution to journalArticle

62 Scopus citations

Abstract

Purified serum paraoxonase (PON1) had been shown to attenuate the oxidation of LDL in vitro. We critically reevaluated the antioxidant properties of serum PON1 in the in vitro assays initiated with copper or the free radical generator 2,2'-azobis-2-amidinopropane hydrochloride (AAPH). The antioxidant activity of different purified PON1 preparations did not correlate with their arylesterase (AE), lactonase, or phospholipase A2 activities or with the amounts of detergent or protein. Dialysis of three of these preparations resulted in a 30-40% loss of their AE activities but in a complete loss of their antioxidant activities. We also followed the distribution of the antioxidant activity during human serum PON1 purification by two purification methods. The antioxidant activity of the anion-exchange chromatography fractions did not copurify with PON1 using either method and could largely be accounted for by the "antioxidant" activity of the detergent present. In conclusion, using the copper or AAPH in vitro assays, no PON1-mediated antioxidant activity was detected, suggesting that the removal of PON1 from its natural environment may impair its antioxidative activity and that this assay with highly purified PON1 may be an inappropriate method with which to study the antioxidative properties of the enzyme.

Original languageEnglish (US)
Pages (from-to)2260-2268
Number of pages9
JournalJournal of lipid research
Volume45
Issue number12
DOIs
StatePublished - Dec 1 2004

Keywords

  • 2,2′-azobis-2-amidinopropane hydrochloride
  • Antioxidants
  • Atherosclerosis
  • Oxidized low density lipoprotein
  • Paraoxonase 1

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Cell Biology

Fingerprint Dive into the research topics of 'Purified human serum PON1 does not protect LDL against oxidation in the in vitro assays initiated with copper or AAPH'. Together they form a unique fingerprint.

  • Cite this