A new method for the measurement of lipoprotein lipase in postheparin plasma using sodium dodecyl sulfate for the inactivation of hepatic triglyceride lipase.
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.
D005260:Female; D006493:Heparin; D006801:Humans; D006949:Hyperlipidemias / Q000201:enzymology*; D007700:Kinetics; D008049:Lipase / Q000037:antagonists & inhibitors / Q000097:blood*; D008071:Lipoprotein Lipase / Q000097:blood*; D008099:Liver / Q000201:enzymology*; D008297:Male; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology*; D014280:Triglycerides
D014280:Triglycerides; D012967:Sodium Dodecyl Sulfate; D006493:Heparin; D008049:Lipase; D008071:Lipoprotein Lipase