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Localization of carotenoids in plasma low‐density lipoproteins studied by surface‐enhanced resonance Raman spectroscopy
Author(s) -
Lin Sa,
Quaroni Luca,
White Wendy S.,
Cotton Therese,
Chumanov George
Publication year - 2000
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/1097-0282(2000)57:4<249::aid-bip6>3.0.co;2-1
Subject(s) - chemistry , monolayer , lycopene , carotenoid , raman spectroscopy , adsorption , resonance (particle physics) , resonance raman spectroscopy , analytical chemistry (journal) , raman scattering , particle (ecology) , photochemistry , organic chemistry , biochemistry , optics , physics , oceanography , particle physics , geology
Surface‐enhanced resonance Raman scattering (SERRS) spectra were measured for the β‐carotene and lycopene carotenoids present in low‐density lipoproteins (LDLs), which were isolated from human plasma and adsorbed on roughened silver surfaces. The silver surface was modified by formation of a self‐assembled monolayer (SAM) of carboxylate‐terminated linear alkanethiols in order to simulate the LDL binding region of the cellular LDL receptor. Thiols of different chain length were used to produce SAMs of varying thicknesses. It was shown that carotenoids are not released from the LDL particle upon adsorption onto the bare and thiol modified silver surfaces. The SERRS studies indicated that β‐carotene and lycopene were present in the shell of the LDL particle. The dependence of SERRS on the distance from the silver surface was different for β‐carotene and lycopene in LDL. This observation suggests that the two carotenoids are located in different places of the LDL particle.