Association of lysolecithin acyltransferase with the high density lipoproteins and its activation by the low density lipoproteins in normal human plasma

Low density human plasma lipoproteins Sf 17+, Sf 13, and Sf 6, high density lipoproteins 2 and 3, and a lipoprotein-free plasma protein fraction were isolated from human plasma by ultracentrifugal methods. It was found that human plasma lipoproteins are immunochemically distinct from the non-lipoprotein containing plasma protein fraction. Lipoprotein fractions of a given hydrated density, isolated from different individuals, were found to be immunochemically indistinguishable by qualitative absorption tests. Qualitative antigenic differences were shown to exist between low density lipoproteins and high density lipoproteins. Quantitative precipitin reactions showed that low density lipoproteins Sf 6 and Sf 13 were immunochemically very similar. However, they differed with respect to the amount of antigen nitrogen required for maximum precipitation. Agar diffusion analyses were performed; the results suggest heterogeneity of lipoproteins by this criterion.

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Improved estimation of cholesteryl ester transfer/exchange activity in serum or plasma.

Clinical Chemistry ◽

10.1093/clinchem/32.2.283 ◽

1986 ◽

Vol 32 (2) ◽

pp. 283-286 ◽

Cited By ~ 116

Author(s):

J E Groener ◽

R W Pelton ◽

G M Kostner

Keyword(s):

Polyethylene Glycol ◽

Cholesteryl Ester ◽

Human Plasma ◽

Dextran Sulfate ◽

Low Density Lipoproteins ◽

High Density ◽

High Density Lipoproteins ◽

Low Density ◽

Routine Assay ◽

Exchange Activity

Abstract This simple, routine assay for measuring cholesteryl ester transfer/exchange activity in human plasma is based on the removal of interfering lipoproteins--very-low-density (VLDL) and low-density lipoproteins (LDL)--by precipitation with polyethylene glycol. High-density lipoproteins (HDL) in the samples do not affect the results. The supernate after precipitation is mixed with [14C]cholesteryl ester-labeled LDL as donor and with HDL as the acceptor for the cholesteryl ester. After incubation for 16 h at 37 degrees C, LDL is separated from HDL by precipitation with dextran sulfate and the radioactivity measured in the supernate, which contains the HDL. The assay is applicable to samples containing as much as 10 mmol of triglycerides per liter. The within-assay CV was 2.7%, the day-to-day CV 6.8%. Results compared well with those by conventional procedures.

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Characterization of plasma lipoproteins separated and purified by agarose-column chromatography

Biochemical Journal ◽

10.1042/bj1390089 ◽

1974 ◽

Vol 139 (1) ◽

pp. 89-95 ◽

Cited By ~ 248

Author(s):

Lawrence L. Rudel ◽

Jason A. Lee ◽

Manford D. Morris ◽

James M. Felts

Keyword(s):

Human Plasma ◽

Column Chromatography ◽

Low Density Lipoproteins ◽

High Density ◽

Plasma Lipoproteins ◽

High Density Lipoproteins ◽

Low Density ◽

Very Low Density Lipoproteins ◽

Simple Method ◽

Lipoprotein Class

1. A simple method for isolation of individual human plasma lipoprotein classes is presented. In this technique, lipoproteins are removed from plasma at d1.225 by ultracentrifugation, after which they are separated and purified by agarose-column chromatography. 2. Three major classes are obtained after agarose-column chromatography. Separation between classes is excellent; more than 95% of the lipoproteins eluted from the column are recovered in the form of a purified lipoprotein class. 3. Each lipoprotein class was characterized immunologically, chemically, electrophoretically and by electron microscopy. A comparison of the properties of the column-isolated lipoproteins was made with very-low-density lipoproteins, low-density lipoproteins, and high-density lipoproteins separated by sequential ultracentrifugation at densities of 1.006, 1.063 and 1.21 respectively. 4. By each criterion, peak-I lipoproteins from the agarose column are the same as very-low-density lipoproteins, peak-II lipoproteins are the same as low-density lipoproteins, and peak-III lipoproteins are the same as high-density lipoproteins. Thus the lipoprotein classes isolated by both methods are similar if not identical. 5. The agarose-column separation technique offers the advantage of a two- to three-fold saving in time. In addition, the column-elution pattern serves as a recording of the size distribution of lipoproteins in plasma. 6. The most complete characterization is reported for human plasma lipoproteins. The results with rhesus-monkey and rabbit lipoproteins were identical.

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