Effect of homocysteinylation on high density lipoprotein physico-chemical properties

Gianna Ferretti, Tiziana Bacchetti, Simona Masciangelo, Virginia Bicchiega

Research output: Contribution to journalArticle

Abstract

High density lipoproteins (HDL) exert a protective effect against homocysteinylation due to the activity of the enzyme paraoxonase/thiolactonase associated to the lipoprotein surface. However, a small amount of N-homocysteinylated HDL (N-Hcy-HDL) is present in human plasma, suggesting that homocysteinylation of plasma lipoproteins occurs in vivo. Aim of the present study was to investigate the effect of homocysteinylation on apoprotein structure and physico-chemical properties of HDL using the analysis of the fluorescent emission spectra of tryptophan and Laurdan (6-dodecanoyl-2-dimethyl-aminonaphthalene). Our results demonstrated that the increase in -SH groups in HDL homocysteinylated in vitro (Hcy-HDL) was associated with apoprotein conformational changes and modifications of physico-chemical properties. A significant decrease of paraoxonase and lactonase activity of HDL bound PON1 has also been observed in Hcy-HDL. A significant decrease of the enzyme activity has been observed also in purified PON1 homocysteinylated following the same experimental conditions used for HDL. Moreover, we demonstrated that oxidized HDL were more susceptible to homocysteinylation with respect to control HDL. The modifications of apoprotein conformation and physico-chemical properties in Hcy-HDL and the decrease of paraoxonase-1 activity could affect the protective effect of HDL against oxidative damage and/or homocysteinylation and could contribute to accelerated atherosclerosis in patients affected by diseases associated with oxidative damage, in renal disorders and in patients affected by genetic or nutritional disorders of homocysteine or folate metabolism.

Original languageEnglish
Pages (from-to)228-235
Number of pages8
JournalChemistry and Physics of Lipids
Volume163
Issue number2
DOIs
Publication statusPublished - Feb 2010

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Keywords

  • ApoAI
  • Atherosclerosis
  • High density lipoproteins (HDL)
  • Homocysteine (Hcy)
  • Homocysteine-thiolactone (HcyT)
  • Lipid peroxidation
  • Paraoxonase (PON1)
  • Thiolactonase (Htase)

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology
  • Organic Chemistry

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