Resonance Raman spectra of beta-carotene in native and modified low-density lipoprotein

Biochem Biophys Res Commun. 1984 Jul 31;122(2):867-75. doi: 10.1016/s0006-291x(84)80114-x.

Abstract

Low-density lipoproteins isolated between density 1.02 and 1.063 g/cm3 from normal fasting human plasma, show strong resonance Raman spectra due to the presence of beta-carotene. Three intense bands, at 1010, 1160 and 1530 cm-1, are assigned to the stretching vibrations of -C-CH3, = C-C = and -C = C- bonds, respectively, of beta-carotene. High-resolution spectra of the 1500-1600 cm-1 region reveal multiple features, suggesting the coexistence of several structural populations of beta-carotene. The modifications of lipoproteins with pH and temperature (30 degrees-42 degrees) change the resonance Raman spectra of beta-carotene. The specific binding of LDL at pH 7.0 by fibroblast cells is suppressed. Our experiments thus suggest that physical and chemical perturbations of plasma lipoproteins modify the lipid-protein interactions and thereby alter the configurational distribution of beta-carotene molecules within these particles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carotenoids / analysis*
  • Cell Line
  • Fasting
  • Fibroblasts / metabolism
  • Humans
  • Kinetics
  • Lipoproteins, LDL / blood*
  • Lipoproteins, LDL / isolation & purification
  • Lipoproteins, LDL / metabolism
  • Receptors, Cell Surface / metabolism
  • Receptors, LDL
  • Spectrum Analysis, Raman / methods
  • Thermodynamics
  • beta Carotene

Substances

  • Lipoproteins, LDL
  • Receptors, Cell Surface
  • Receptors, LDL
  • beta Carotene
  • Carotenoids