Binding of low-density lipoprotein to heparin-Sepharose : Characterization and inhibition by serum high-molecular-weight components
article
In this study, the interaction of human serum low-density lipoprotein (LDL) with heparin immobilized on Sepharose was reinvestigated. Binding of isolated LDL (stabilized with human serum albumin (HSA)) was compared with that of LDL in full serum. (1) Binding of isolated LDL was slightly decreased by CaCl2 and was not affected by MgCl2. In contrast, with full serum LDL binding was increased by these divalent cations. (2) In both situations, binding of LDL was saturable, but the maximum degree of binding that could be reached was much higher with isolated LDL than with LDL in full serum. This could be ascribed to an inhibitory action of a factor found in the d>1.24 fraction of serum. (3) The effect of this factor was diminished in the presence of CaCl2 or MgCl2, which suggests that the stimulation of LDL binding by these cations in full serum is due to suppression of the inhibitory activity of this factor. (4). The inhibitory factor in the d>1.24 fraction can be partially purified by absorption to heparin-Sepharose, followed by elution with 6 M guanidine chloride. The resulting preparation had a 30- to 50-fold higher specific activity. Attempts to purify the factor further resulted in loss of activity. (5) The activity is decreased upon treatment with trypsin and also upon acetylation or reduction with dithiothreitol, indicating that free amino groups and S-S bridges are essential. Copyright © 1988 Published by Elsevier B.V.
Chemicals/CAS: heparin, 37187-54-5, 8057-48-5, 8065-01-8, 9005-48-5; sepharose, 61970-08-9; Blood Proteins; Calcium, 7440-70-2; Heparin, 9005-49-6; Lipoproteins, LDL; Magnesium, 7439-95-4; Sepharose, 9012-36-6
Chemicals/CAS: heparin, 37187-54-5, 8057-48-5, 8065-01-8, 9005-48-5; sepharose, 61970-08-9; Blood Proteins; Calcium, 7440-70-2; Heparin, 9005-49-6; Lipoproteins, LDL; Magnesium, 7439-95-4; Sepharose, 9012-36-6
Topics
TNO Identifier
230504
ISSN
00052760
Source
Biochimica et Biophysica Acta - Lipids and Lipid Metabolism, 960(3), pp. 365-373.
Pages
365-373
Files
To receive the publication files, please send an e-mail request to TNO Repository.