title: Partial characterization of the bile salt-dependent triacylglycerol lipase from the leopard shark pancreas.
abstract: Leopard shark triacylglycerol lipase has been characterized as a crude pancreatic preparation. The enzyme demonstrated an absolute requirement for trihydroxy bile salts for activity with natural bile salts of the shark giving a 4-fold greater stimulation of activity than pure sodium taurocholate. Bile salts also protected the enzyme from apparent inactivation by p-chloromercuribenzoate and trypsin treatment. The shark lipase demonstrated a temperature optimum of 36 degrees C and was rapidly inactivated at 50 degrees C even in the presence of bile salts. Divalent metal ions were required for activity with Ca2+ providing the greatest stimulation. At 22 degrees C, pH 8.5 and in the presence of natural bile salts, the apparent V was about 0.6 mumol fatty acid released/min per mg protein. The shark enzyme hydrolyzed over 90% of the fatty acids from trioleovylglycerol and methyl esters of pancreatic lipase-resistant fatty acids were hydrolyzed at the same rate as typical fatty acid methyl esters. Hydrolysis of triacylglycerol proceeded about ten-times faster than wax ester hydrolysis. The kinetic properties of the leopard shark enzyme were compared to other bile salt-dependent lipolytic enzymes. Pancreatic lipase activity was not detected.
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000494:pharmacology*; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D008053:Lipid Mobilization / Q000187:drug effects; D010179:Pancreas / Q000201:enzymology*; D012754:Sharks / Q000378:metabolism*; D013045:Species Specificity; D014280:Triglycerides
chemical_list: D001647:Bile Acids and Salts; D014280:Triglycerides; D008049:Lipase