Comparative proteomic profiling of plasma very-low-density and low-density lipoproteins.

BACKGROUND: Low-density lipoprotein (LDL) is a natural metabolite of very-low-density lipoprotein (VLDL) in the circulation. Systematic investigation of total protein components and dynamics might provide insights into this normal metabolic process.

METHODS: VLDL and LDL were purified from normolipidemia pooled plasma by gradient ultracentrifugation with either ionic or non-ionic media. The protein contents were compared by liquid chromatography tandem mass analyses based on isobaric tag for relative and absolute quantitation and two-dimensional gel electrophoresis.

RESULTS: Our comparative lipoproteomes revealed 21 associated proteins. Combined with Western blot analysis, and on the basis of the differential expression levels we classified them into 3 groups: (i) VLDL>LDL [apolipoprotein (apo) A-IV, apo(a), apoCs, apoE, apoJ and serum amyloid A-4]; (ii) VLDL
CONCLUSIONS: This study revealed the VLDL- and LDL lipoproteomes and the full-spectrum protein changes during physiological VLDL-to-LDL transition. It provides a valuable dataset VLDL and LDL proteomes potentially applied to the development of diagnostics.