Author/Editor		Kveder, Marina; Pifat, Greta; Pečar, Slavko; Schara, Milan; Ramos, Pilar; Esterbauer, Hermann
Title		Nitroxide reduction with ascorbic acid in spin labeled human plasma LDL and VLDL
Type		članek
Source		Chem Phys Lipids
Vol. and No.		Letnik 85
Publication year		1997
Volume		str. 1-12
Language		eng
Abstract		The LDL and VLDL were spin labeled with Tempo which partitions both in the aqueous and lipid phase. The ESR spectra were measured in the equilibrium state as well as during the reduction of the spin label with ascorbic acid. The kinetics of the concentration decay curves was parametrized with two exponentials. The theoretical simulation of the experimental spectra revealed a drastic linewidth narrowing in the VLDL samples exposed to the ascorbic acid. Since the transport properties of the specific monolayer are reflected in the observed reaction rates, the analysis of the fatty acid composition of phospholipids, triglycerides and cholesterol esters in LDL and VLDL was performed. It is concluded that different lipid packing at the surface of LDL and VLDL might be the consequence of different intemolecular forces between phospholipids and cholesterol. This finding was connected to the experimentally detected different reaction kinetics in LDL and VLDL as well as their different susceptibility to the ESR linebroadening effects during the nonequilibrium conditions of the spin label reduction with ascorbic acid.
Descriptors		ASCORBIC ACID CYCLIC N-OXIDES LIPOPROTEINS, VLDL LIPOPROTEINS, LDL SPIN LABELS CHOLESTEROL ESTERS FATTY ACIDS LIPOPROTEINS PROTEINS TRIGLYCERIDES OXIDATION-REDUCTION ELECTRON SPIN RESONANCE SPECTROSCOPY