Metal Ion Complexes of EDTA: A Solute System for Density Gradient Ultracentrifugation Analysis of Lipoproteins

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• 作者：Brian D. Hosken ; Steven L. Cockrill ; and Ronald D. Macfarlane
• 刊名：Analytical Chemistry
• 出版年：2005
• 出版时间：January 1, 2005
• 年：2005
• 卷：77
• 期：1
• 页码：200 - 207
• 全文大小：176K
• 年卷期：v.77,no.1(January 1, 2005)
• ISSN：1520-6882

文摘

In the study reported here, we apply some of the featuresof coordination chemistry to solve a long-standing problemin the separation and characterization of lipoproteinparticles. Lipoproteins are circulating micelle-like particles responsible for lipid transport. They exist in threemajor classes: very-low-density lipoprotein, low-densitylipoprotein, and high-density lipoprotein in well-defineddensity ranges using the density gradient ultracentrifugation (DGU) method. The analytical instrumentation ofDGU has improved over the years in response to clinicalevidence that certain lipoprotein species are linked to ahigh risk for developing cardiovascular disease. A long-standing problem has been a lack of appropriate gradient-forming solutes that can generate a useful gradient froma homogeneous solution. We have found that a new classof solutes based on metal ion complexes has the potentialof providing a wide selection of compounds where thefeatures can be modulated by choice of ligand, complexingmetal ion, and counterion. In this study, we have chosenthe cesium salt of BiEDTA (CsBiEDTA) and have investigated the dynamics of density gradient formation in theultracentrifuge. We show that a useful density gradientcan be formed within a few hours beginning with ahomogeneous solution. We also present data on themigration behavior of lipoproteins under gradient-formingconditions and show that high-resolution density profilescan be obtained with good precision. The resolution ofthe CsBiEDTA profile is compared with those obtainedusing high molecular weight organic solutes.