Characterization of lipoprotein particles isolated by immunoaffinity chromatography. Particles containing A-I and A-II and particles containing A-I but no A-II.
Two populations of A-I-containing lipoprotein particles: A-I-containing lipoprotein with A-II (Lp (A-I with A-II], and A-I-containing lipoprotein without A-II (Lp (A-I without A-II] have been isolated from plasma of 10 normolipidemic subjects by immunoaffinity chromatography and characterized. Both types of particles possess alpha-electrophoretic mobility and hydrated density in the range of plasma high-density lipoproteins (HDL). Lp (A-I without A-II) and Lp (A-I with A-II) are heterogeneous in size. Lp (A-I without A-II) comprised two distinct particle sizes with mean apparent molecular weight and Stokes diameter of 3.01 X 10(5), and 10.8 nm for Lp (A-I without A-II)1, and 1.64 X 10(5), and 8.5 nm for Lp (A-I without A-II)2. Lp (A-I with A-II) usually contained particles of at least three distinct molecular sizes with mean apparent molecular weight and Stokes diameter of 2.28 X 10(5) and 9.6 nm for Lp (A-I with A-II)1, 1.80 X 10(5) and 8.9 nm for Lp (A-I with A-II)2, and 1.25 X 10(5) and 8.0 nm for Lp (A-I with A-II)3. Apoproteins C, D, and E, and lecithin:cholesterol acyltransferase (LCAT) were detected in both Lp (A-I without A-II) and Lp (A-I with A-II) with most of the apoprotein D, and E, and LCAT (EC 2.3.1.43) in Lp (A-I with A-II) particles. Lp (A-I without A-II) had a slightly higher lipid/protein ratio than Lp (A-I with A-II). Lp (A-I with A-II) had an A-I/A-II molar ratio of approximately 2:1. The percentage of plasma A-I associated with Lp (A-I without A-II) was highly correlated with the A-I/A-II ratio of plasma (r = 0.96, n = 10). The variation in A-I/A-II ratio of HDL density subfractions therefore reflects different proportions of two discrete types of particles: particles containing A-I and A-II in a nearly constant ratio and particles containing A-II but no A-II. Each type of particle is heterogeneous in size and in apoprotein composition.
D000818:Animals; D000918:Antibody Specificity; D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001054:Apolipoproteins A / Q000097:blood*; D001057:Apolipoproteins E / Q000097:blood; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D002846:Chromatography, Affinity / Q000379:methods; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006041:Goats / Q000276:immunology; D006801:Humans; D005779:Immunodiffusion; D008074:Lipoproteins / Q000097:blood*; D008075:Lipoproteins, HDL / Q000097:blood; D008297:Male; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000097:blood; D011817:Rabbits; D014461:Ultracentrifugation
D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001054:Apolipoproteins A; D001057:Apolipoproteins E; D008076:Cholesterol, HDL; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D002784:Cholesterol; D007862:Phosphatidylcholine-Sterol O-Acyltransferase