Biochemical characterization of the three major subclasses of lipoprotein A-I preparatively isolated from human plasma

Biochemistry. 1993 Nov 23;32(46):12372-9. doi: 10.1021/bi00097a014.

Abstract

Apolipoprotein (apo) A-I is the major protein constituent of plasma high-density lipoproteins (HDL). HDL consist of two major classes of apoA-I-containing lipoproteins: LpA-I and LpA-I:A-II. LpA-I includes heterogeneous lipoprotein particles that differ in size and hydrated density. LpA-I was isolated by immunoaffinity chromatography from the fasting plasma of 24 normal human subjects and separated by gel filtration chromatography. Three major subclasses of LpA-I were eluted: large (Lg-LpA-I), medium (Md-LpA-I), and small LpA-I (Sm-LpA-I). By nondenaturing gradient PAGE, Lg-LpA-I, Md-LpA-I, and Sm-LpA-I had mean Strokes diameters of 10.8 +/- 0.5, 8.9 +/- 0.5, and 7.5 +/- 0.3 nm, respectively. The lipid/protein ratios were 1.25 +/- 0.12 for Lg-LpA-I, 0.75 +/- 0.10 for Md-LpA-I, and 0.38 +/- 0.08 for Sm-LpA-I. Lg-LpA-I was relatively lipid and cholesteryl ester rich compared with Md-LpA-I and Sm-LpA-I. Sm-LpA-I contained phospholipids as the major lipid component. ApoA-I was the major apolipoprotein in all LpA-I subfractions, whereas apoE was present only in Lg-LpA-I and apoA-IV was associated with both Md-LpA-I and Sm-LpA-I. All three LpA-I subclasses exhibited predominantly alpha mobility on agarose electrophoresis. Lg-LpA-I migrated as a diffuse band in the fast alpha position, whereas Md-LpA-I and Sm-LpA-I migrated to the slow alpha position.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Apolipoprotein A-I / chemistry
  • Apolipoprotein A-I / metabolism
  • Carrier Proteins / metabolism
  • Cell Line
  • Cholesterol / metabolism
  • Cholesterol Ester Transfer Proteins
  • Chromatography, Gel
  • Electrophoresis, Agar Gel
  • Female
  • Glycoproteins*
  • Humans
  • Lipoprotein(a) / analogs & derivatives*
  • Lipoprotein(a) / blood
  • Lipoprotein(a) / chemistry
  • Male
  • Mice
  • Protein Binding
  • Sterol O-Acyltransferase / metabolism

Substances

  • Apolipoprotein A-I
  • CETP protein, human
  • Carrier Proteins
  • Cholesterol Ester Transfer Proteins
  • Glycoproteins
  • Lipoprotein(a)
  • lipoprotein A-I
  • Cholesterol
  • Sterol O-Acyltransferase