Lipoprotein lipase in heart and myocytes: characteristics with intralipid as substrate.
1. Intralipid is a suitable substrate for measuring lipoprotein lipase activity in the presence of other triacylglycerol lipases in heart and myocytes. 2. Triacylglycerol lipase activity in heart and myocytes was increased 10-fold in the presence of serum at pH 7.4 and 8.1. The serum-stimulated activity in myocytes was 95% inhibited by saturating concentrations of antiserum to lipoprotein lipase. 3. Both heparin-releasable and non-releasable lipoprotein lipase fractions had similar Km values for Intralipid and a similar pattern of inhibition by high density lipoprotein but different responses to heparin. 4. Isoproterenol did not alter lipoprotein lipase activity in cardiac myocytes.
Perenna Rogers
M
M
Department of Biochemistry and Genetics, Medical School, The University, Newcastle upon Tyne, UK.
Dale
A
A
Etienne
J
J
Younan
S
S
D000818:Animals; D002478:Cells, Cultured; D006493:Heparin / Q000494:pharmacology; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D013379:Substrate Specificity
D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D006493:Heparin; D008071:Lipoprotein Lipase