SEPARATION AND QUANTITATION OF APOLIPOPROTEIN B-48 AND OTHER APOLIPOPROTEINS BY DYNAMIC SIEVING CAPILLARY ELECTROPHORESIS

Apolipoprotein-B-48 is a structural protein exclusively associated wit h post-prandial lipoproteins (chylomicrons). Apolipoprotein B-48 would be a useful marker to monitor the kinetics of chylomicrons in vivo, h owever, its quantitation is limited because of a low concentration in plasma and lack of specific antibodies. Dynamic sieving capillary elec trophoresis (DSCE) has recently become widely available for the separa tion of nanomolar quantities of proteins by size and electrophoretic m obility. Here we describe the potential of DSCE to accurately quantita te apolipoprotein mass in one mi of plasma. Separation of human serum apolipoproteins was achieved through an uncoated fused silica glass ca pillary column with quantitation based on area response at 220 nm. The retention times for human apolipoprotein B-48, apolipoprotein B100 an d albumin were 5.96 min +/- 0.57%, 10.21 min +/- 0.72%, and 6.56 min /- 0.4%, respectively (phase-standardized to internal reference). A si gnificant correlation (r = 0.99) was observed between apolipoprotein c oncentrations and peak area response for mass ranges of 30-400 mu g/ml . DSCE provides an alternative method for quantifying apolipoprotein B -48 and therefore, may be useful for studying postprandial lipoprotein metabolism.