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Lipolysis of very low density lipoproteins by heparan sulfate proteoglycan-bound lipoprotein lipase

Author: Man, F.H.A.F. de · Beer, F. de · Laarse, A. van der · Smelt, A.H.M. · Havekes, L.M.
Type:article
Date:1997
Institution: Gaubius Instituut TNO
Source:Journal of Lipid Research, 12, 38, 2465-2472
Identifier: 234255
Keywords: Animals · Binding, Competitive · Cattle · Fatty Acids · Heparan Sulfate Proteoglycans · Heparin Lyase · Humans · Iodine Radioisotopes · Kinetics · Lipolysis · Lipoprotein Lipase · Lipoproteins, VLDL · Protein Binding · Radioligand Assay · Triglycerides

Abstract

An in vitro assay to study lipolysis of very low density lipoproteins (VLDL) by heparan sulfate proteoglycan (HSPG-bound lipoprotein lipase (LPL) was developed. Optimal conditions for VLDL lipolysis by HSPG-bound LPL were obtained by incubating plastic wells with 0.5 μg HSPG and 1.5 μg LPL, subsequently. Control experiments with heparinase indicate that at least 90% of the LPL activity is derived from LPL bound to heparan sulfate chains. For HSPG-LPL-mediated lipolysis, the apparent K(m) and V(max) values were 0.36 ± 0.11 mM VLDL-triglycerides and 1.2 ± 0.1 μM free fatty acids/min·ng LPL, respectively. The mean intra-assay and inter-assay coefficients of variance were 5% and 8%, respectively.