PMID: 7016193Apr 23, 1981Paper

Proteolytic degradation of low density lipoproteins by arterial smooth muscle cells: the role of individual cathepsins

Biochimica Et Biophysica Acta
D S Leake, T J Peters

Abstract

Low density lipoproteins have been implicated in the pathogenesis of atherosclerosis. A study has therefore been made of their proteolytic degradation by homogenates of cultured smooth muscle cells from the pig aorta. The pH optimum of proteolysis of 125I-labelled low density lipoproteins was 4.25, thus suggesting the involvement of lysosomal cathepsins. Proteolysis at acid pH started to become saturated at low density lipoprotein concentrations of approx. 20 microgram of protein/ml, but did not obey Michaelis-Menten kinetics. After a lag period of approx. 10 min, proteolytic degradation was linear with time up to at least 4 h incubation, but showed a sigmoidal relationship with homogenate concentration. When cathepsin D was inhibited by pepstatin, the proteolysis of 125I-labeled low density lipoproteins was inhibited by more than 90%, whereas when cathepsin B was inhibited by leupeptin, the rate of proteolysis decreased by approx. 50%. Antipain, which inhibits both cathepsins A and B, did not inhibit proteolysis any more than leupeptin, thus suggesting a minor role, if any, for cathepsin A. a combination of pepstatin and either leupeptin or antipain inhibited proteolysis completely. Cathepsins B and D acted synergistically in ...Continue Reading

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Citations

Jun 15, 1989·European Journal of Biochemistry·M E Knowles, D S Leake
Mar 1, 1985·Arteriosclerosis : an Official Journal of the American Heart Association, Inc·P S BachorikP O Kwiterovich
Mar 6, 2004·Circulation Research·Farouc A Jaffer, Ralph Weissleder
Aug 13, 2002·Arteriosclerosis, Thrombosis, and Vascular Biology·Allan R BrasierMohsen S Eledrisi
Jan 1, 1986·The Journal of Membrane Biology·U ScheuringD Schubert
Apr 22, 2018·Nature Reviews. Cardiology·Cong-Lin LiuGuo-Ping Shi

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