TY - JOUR
T1 - Triacylglycerol lipase, monoacylglycerol lipase and phospholipase activities of highly purified rat hepatic lipase
AU - Jensen, Gordon L.
AU - Daggy, Bruce
AU - Bensadoun, Andre
N1 - Funding Information:
This research was supported by NIH grants Hl-14990 and HL-24873. We express our appreciation for the lecithin: cholesterol acyltransferase assays by Stephen Behr and the technical assistance of Gillian Tufts and Owen McConville.
PY - 1982/3/12
Y1 - 1982/3/12
N2 - Highly purified rat hepatic lipase (NaCl-resistant, alkaline pH optimum) was studied to evaluate whether the enzyme has triacylglycerol lipase, monoacylglycerol lipase and phospholipase activities. Enzyme exhibiting a single band by SDS-polyacrylamide gel electrophoresis and having a specific activity eight times greater than that in any previous report was utilized. The ratios of the different lipolytic activities to each other remained constant throughout a multistep hepatic lipase purification. The lipolytic activities coeluted by gel filtration on Ultrogel AcA 34. Column isoelectric focusing of the highly purified enzyme revealed comigration of the lipolytic activities. Thermal inactivation produced similar decay curves for the different activities. Immune titration curves for the different activities with specific antibody against hepatic lipase were essentially identical. These findings indicate that hepatic lipase is a single enzyme molecule which has triacylglycerol lipase, monoacylglycerol lipase and phospholipase activities with artificial substrates. To study these lipolytic activities further, highly purified hepatic lipase was subjected to limited digestion by specific proteases. The triacylglycerol lipase activity was more sensitive to proteolytic destruction than either of the other two activities.
AB - Highly purified rat hepatic lipase (NaCl-resistant, alkaline pH optimum) was studied to evaluate whether the enzyme has triacylglycerol lipase, monoacylglycerol lipase and phospholipase activities. Enzyme exhibiting a single band by SDS-polyacrylamide gel electrophoresis and having a specific activity eight times greater than that in any previous report was utilized. The ratios of the different lipolytic activities to each other remained constant throughout a multistep hepatic lipase purification. The lipolytic activities coeluted by gel filtration on Ultrogel AcA 34. Column isoelectric focusing of the highly purified enzyme revealed comigration of the lipolytic activities. Thermal inactivation produced similar decay curves for the different activities. Immune titration curves for the different activities with specific antibody against hepatic lipase were essentially identical. These findings indicate that hepatic lipase is a single enzyme molecule which has triacylglycerol lipase, monoacylglycerol lipase and phospholipase activities with artificial substrates. To study these lipolytic activities further, highly purified hepatic lipase was subjected to limited digestion by specific proteases. The triacylglycerol lipase activity was more sensitive to proteolytic destruction than either of the other two activities.
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U2 - 10.1016/0005-2760(82)90130-8
DO - 10.1016/0005-2760(82)90130-8
M3 - Article
C2 - 7074125
AN - SCOPUS:0020036590
SN - 0005-2760
VL - 710
SP - 464
EP - 470
JO - Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
JF - Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
IS - 3
ER -