Journal of Applied Physiology, Vol 39, Issue 6 1022-1033, Copyright © 1975 by American Physiological Society
Purified postheparin plasma lipoprotein lipase in primary hyperlipoproteinemias
D. Ganesan, R. H. Bradford, G. Ganesan, W. J. McConathy, P. Alaupovic and H. B. Bass
Purified postheparin plasma lipoprotein lipase (LPL) of normolipidemic and
primary hyperlipoproteinemic subjects was characterized by lipoprotein C
polypeptide activation and specificity for triglycerides in chylomicrons
and VLDL. Chromatography of normal LPL on Sephadex G-100 resulted in two
protein peaks, LPLC-1 (activated by C-I but not C-II) and LPLC-II
(activated by C-II but not C-I). LPL from type I hyperlipoproteinemic
subjects was not activated by C-I and C-II activation was reduced to 40% of
control. Hydrolysis of chylomicron and VLDL triglycerides was severely
impaired. Although chromatography of type I LPL resulted in two protein
peaks, the protein peak corresponding to LPLC-I did not exhibit lipolytic
activity and LPLC-II was reduced to 50% of control in protein and enzyme
specific activity. Type III LPL was normal in respect to LPLC-I while
LPLC-II averaged 40% of control. Hydrolysis of chylomicron and VLDL was
reduced to 50% and 10% of control, respectively. An etiological implication
for LPLC-I and/or LPLC-II in type I and III hyperlipoproteinemias is
suggested.
