A new method for the measurement of lipoprotein lipase in postheparin plasma using sodium dodecyl sulfate for the inactivation of hepatic triglyceride lipase

• Published in: Journal of lipid research 1979-05, Vol.20 (4), p.548-556
• Main Authors: Baginsky, M L, Brown, W V
• Format: Article
• Language: English
• Subjects: Female; Heparin; Humans; Hyperlipidemias - enzymology; Kinetics; Lipase - antagonists & inhibitors; Lipase - blood; Lipoprotein Lipase - blood; Liver - enzymology; Male; Sodium Dodecyl Sulfate - pharmacology; Triglycerides
• ISSN: 0022-2275; 1539-7262
• DOI: 10.1016/S0022-2275(20)40610-8

Lipoprotein lipase (LPL) and hepatic triglyceride lipase (H-TGL) are lipolytic activities found in postheparin plasma. A simple and precise method for the direct determination of LPL in postheparin plasma is described. Pre-incubations of this plasma (45–60 min at 26 degrees C) with sodium dodecyl sulfate (35–50 mM) in 0.2 M Tris-HCl buffer, pH 8.2, results in the inactivation of H-TGL, while leaving LPL fully active. Direct determination of H-TGL is done in a separate aliquot of the same postheparin plasma sample using previously reported assay conditons that do not measure LPL. The sodium dodecyl sulfate-resistant lipolytic activity has the characteristics of LPL as judged by a) its activation by serum and by apolipoprotein C-II; b) its inactivation (over 90%) by 0.75 M NaCl; and c) its inactivation by a specific antiserum. No sodium dodecyl sulfate-resistant activity was found in postheparin plasma from a patient with LPL deficiency (primary type I hyperlipoproteinemia). An excellent correlation of values was obtained (r = 0.99) for 30 samples assayed after sodium dodecyl sulfate treatment and after immuno-inactivation of H-TGL. The intra-assay coefficient of variation was +/- 11% and 4% before and after normalization of values, respectively.