The binding of acetic anhydride- and citraconic anhydride-modified human low-density lipoprotein to mouse peritoneal macrophages The evidence for separate binding sites

Anthony J. Valente, K. W. Walton

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Human plasma low-density lipoprotein (LDL) was modified chemically with either the monocarboxylic acid derivative, acetic anhydride, or the dicarboxylic acid derivative, citraconic anhydride, reagents which react principally with the lysine residues of protein. The modifications increased the net negative charge on the LDL particles, with citraconyl-LDL displaying a greater negative charge than acetylated LDL. Neither the antigenic reactivity nor the overall gross protein/lipid composition of the LDL were affected by the modification procedures, although a small reduction in the total cholesterol content was observed. The altered LDL species lost the ability to bind to the high-affinity cell surface B/E receptor but both bound to mouse peritoneal macrophages with saturable high-affinity kinetics. At 4°C, the macrophages bound 125I-labelled citraconyl-LDL more avidly (K = 21 · 10-3 ml/ng) than they bound labelled acetyl-LDL(K = 2 · 10-3 ml/ng). Competitive inhibition studies indicated that acetyl-LDL and citraconyl-LDL were bound to non-identical sites on the macrophage monolayer surface and that the binding site for citraconyl-LDL was also different from that recognized by hypercholesterolaemic rabbit plasma VLDL (βVLDL).

Original languageEnglish (US)
Pages (from-to)16-24
Number of pages9
JournalBiochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
Volume792
Issue number1
DOIs
Publication statusPublished - Jan 17 1984

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Keywords

  • (Mouse macrophage)
  • Chemical modification
  • LDL
  • Lipoprotein binding

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Endocrinology

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