Document Detail

HDL3 degradation by proteases in isolated rat intestinal mucosal cells.
MedLine Citation:
PMID:  6337644     Owner:  NLM     Status:  MEDLINE    
Human 125I-labelled HDL3 is degraded by isolated rat intestinal mucosal cells. In our experimental conditions, lipoprotein degradation occurred by two different mechanisms. In one, lipoprotein was degraded within the cell, following binding and internalisation. In the other, degradation occurred in the medium, which seemed to contain protease activity released from cells during incubation. Though lipoprotein-deficient serum apparently interfered with degradation in the medium, bovine serum albumin had no such effect. The lysosomal inhibitor, chloroquine, reduced degradation by 60% without inhibiting HDL binding. Intestinal cell extracts contained at least two different proteases, with pH optima of 4.5 and 8.0, respectively. Comparing HDL and LDL degradation on a molar basis, more HDL particles were degraded by the cell-free extracts at pH 4.5. This degradation was activated by dithiothreitol and was inhibited by iodoacetic acid. From these observations we conclude that HDL3 is taken up by the rat intestinal mucosal cell through a specific binding site and subsequently degraded by a thiol-dependent protease in the lysosome.
N Suzuki; N Fidge; P Nestel
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  750     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  1983 Mar 
Date Detail:
Created Date:  1983-04-07     Completed Date:  1983-04-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  457-64     Citation Subset:  IM    
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MeSH Terms
Binding Sites
Culture Media / analysis
Intestinal Mucosa / enzymology*
Iodine Radioisotopes / diagnostic use
Lipoproteins, HDL / metabolism*
Lipoproteins, HDL3
Peptide Hydrolases / metabolism*
Rats, Inbred Strains
Reg. No./Substance:
0/Culture Media; 0/Iodine Radioisotopes; 0/Lipoproteins, HDL; 0/Lipoproteins, HDL3; EC 3.4.-/Peptide Hydrolases

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