Title : Characterization of human
apolipoprotein B100 oligosaccharides in
LDL subfractions derived from normal and hyperlipidemic plasma: deficiency of alpha-N-acetylneuraminyllactosyl-ceramide in light and
small dense LDL particles
Abstract :
- The carbohydrate composition of apolipoprotein (apo) B100 , particularly its degree of sialylation , may contribute to the atherogenic properties of low-density lipoprotein ( LDL )
- We analyzed LDL apoB100 glycans derived from normolipidemic, hypercholesterolemic, and hypertriglyceridemic diabetic subjects
- Using exoglycosidase carbohydrate sequencing and matrix-assisted laser desorption/ionization mass spectrometry to analyze fluorescently labeled oligosaccharides , we report evidence for several carbohydrates not previously identified on apoB100 , including truncated complex biantennary N-glycans and hybrid N-glycans.
- The distribution and diversity of the apoB100 glycans isolated from all individuals was highly conserved
- The N-glycan composition of apoB100 derived from five LDL subpopulations (LDL1, d = 1.018-1.023; LDL2, d = 1.023-1.030; LDL3, d = 1.030-1.040; LDL4, d = 1.040-1.051; LDL5, d = 1.051-1.065 g/ml) did not vary in normolipidemic or hypercholesterolemic subjects
- Furthermore, we found no evidence for "desialylated" apoB100 glycans in any of the samples analyzed
- Analysis of the most abundant LDL ganglioside, alpha-N-acetylneuraminyllactosyl-ceramide, revealed a deficiency in small dense LDL and in the most buoyant subpopulation
- These data provide a novel explanation for the apparent deficiency of sialic acid in small dense LDL and indicate that the global apoB100 N-glycan composition is invariable in the patient groups studied