Hydrolysis of triacylglycerol arachidonic and linoleic acid ester bonds by human pancreatic lipase and carboxyl ester lipase.
The hydrolysis of polyenoic fatty acid ester bonds with pure human colipase-dependent lipase, with carboxyl ester lipase (CEL) and with these enzymes in combination was studied, using [3H]arachidonic- and [14C]linoleic acid-labelled rat chylomicrons as a model substrate. During the hydrolysis with colipase-dependent lipase, the amount of 3H appearing in 1,2-X-diacylglycerol (DG) markedly exceeded that of 14C. When CEL was added in addition this [3H]DG was efficiently hydrolyzed. CEL alone hydrolyzed the triacylglycerol (TG) at a low rate. The hydrolysis pattern with human duodenal content was similar to that seen with colipase-dependent lipase and CEL in combination. Increasing the concentration of taurodeoxycholate (TDC) and taurocholate (TC) or of TDC alone stimulated the hydrolysis of [3H]- and [14C]TG, but increased the accumulation of labelled DG that could act as substrate for CEL. It is suggested that very-long-chain polyenoic fatty acids of DG formed during the action of the colipase-dependent lipase on TG containing these fatty acids may be a physiological substrate for CEL.
Chen
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Q
Department of Medicine, University of Lund, Sweden.
Sternby
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B
Nilsson
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A
D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D001647:Bile Acids and Salts / Q000494:pharmacology; D043182:Carboxylesterase; D002265:Carboxylic Ester Hydrolases / Q000502:physiology*; D002914:Chylomicrons / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D066298:In Vitro Techniques; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism; D008049:Lipase / Q000502:physiology*; D010179:Pancreas / Q000201:enzymology; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism*
D001095:Arachidonic Acids; D001647:Bile Acids and Salts; D002914:Chylomicrons; D008041:Linoleic Acids; D014280:Triglycerides; D016718:Arachidonic Acid; D019787:Linoleic Acid; D002265:Carboxylic Ester Hydrolases; D043182:Carboxylesterase; D008049:Lipase