The involvement of low-density lipoprotein in hemin transport potentiates peroxidative damage

Yury I. Miller, Yana Felikman, Nurith Shaklai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Hemin binds to isolated low-density lipoprotein (LDL) and thereby triggers LDL oxidation. In this study we investigated whether hemin can get together with LDL under physiological conditions. The relative affinity of three blood components to free hemin was as follows: RBCM < LDL < albumin. At physiological molar ratio of LDL/albumin all the hemin was bound to albumin. In molar excess of albumin over hemin, existing even under pathological conditions, albumin served as an efficient antioxidant for the plasma hemin-induced LDL oxidation. RBCM-embedded hemin, unlike plasma hemin, affected LDL: the mobile hemin was transferred from RBCM to LDL in the absence of albumin, whereas in the presence of albumin most of the mobile hemin finally reached the albumin but partially via LDL. Thus, a transient hemin is built up in LDL. This transient hemin triggered LDL oxidation which was not inhibited but rather promoted by albumin. The involvement of albumin in this oxidation was explained by its acting as a pump thereby increasing the transient hemin in LDL. It is suggested that increased membrane hemin level as in hemoglobinopathies and/or excess LDL in dyslipidemia provide conditions for hemin-induced LDL oxidation.

Original languageEnglish
Pages (from-to)119-127
Number of pages9
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Volume1272
Issue number2
DOIs
StatePublished - 17 Oct 1995

Keywords

  • Albumin
  • Hemin
  • Low-density lipoprotein
  • Oxidation
  • Red blood cell membrane

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