[Carbohydrate composition of native and desialylated low density lipoproteins in the plasma of patients with coronary atherosclerosis]

Abstract

The monosaccharide content was examined in apoprotein B and lipids of total low density lipoprotein (LDL) preparations isolated from the blood of healthy individuals and patients with coronary atherosclerosis, as well as in desialylated and sialylated LDL obtained by affinity chromatography on Ricinus Communis Agglutinin-agarose. The glycoconjugates of total apoprotein-B of healthy subjects' LDL were found to consist of N-acetylglycosamine, galactose, mannose and sialic acid in a molar ratio of 2:1:2.5:1. The content of protein-bound neutral sugars was the same in healthy subjects and patients, while there was a lower sialic acid amount in the patients. The level of protein-bound sialic acid in patients' desialylated LDL was 2- to 3-fold lower than that in sialylated LDL. In contrast to apoprotein-B glycoconjugated, the lipid-bound carbohydrate chains of total LDL preparations had N-acetylgalactosamine and glucose, but not mannose. In total LDL from patients, the content of all lipid-bound carbohydrates was 1.5- to 4-fold lower than that in LDL from healthy subjects. In healthy subjects and in patients alike, the neutral sugar content of a lipid subfraction of desialylated LDL was lower than in those of sialylated LDL. It is concluded that atherogenic desialylated LDL differ from non-atherogenic sialylated LDL in neutral sugar levels.