Physico-chemical modifications in desialylated low density lipoproteins

Background and Aim: Chemical modifications such as peroxidation or desialyl ation represent an atherogenic modification of low density lipoprotein (LDL ). The aim of our study was to investigate the effect of desialylation indu ced by neuraminidase on LDL structural organization. Methods and Results: We investigated the effect of desialylation induced in vitro by neuraminidase on physical properties such as polarity and fluidit y by fluorescent methods. A redshifted position of the emission maximum of tryptophan fluorescence and a decrease in the tryptophan fluorescence sugge sted that sialic acid removal induced some modifications in the apo B-100 s tructure. Moreover, the red-shift of the emission maximum of the polarity-s ensitive probe Laurdan indicates an increase in polarity in the microenviro nment of the probe in desialylated-LDL(Ds-LDL) with respect to untreated LD L. A significant decrease in fluorescence polarization indicating a decreas e in the order was also noted in Ds-LDL. Conclusions: Our results show that desialylation induces changes in polarit y and fluidify that could be responsible for their reduced susceptibility t o oxidative stress.