Pancreatic lipase, human substrate specificity

Selected entries from Methods in Enzymology [vol, page(s)] Detergent-resistant phospholipase Ai from Escherichia coll membranes, 197, 309 phospholipase Ai activity of guinea pig pancreatic lipase, 197, 316 purification of rat kidney lysosomal phospholipase Ai, 197, 325 purification and substrate specificity of rat hepatic lipase, 197, 331 human postheparin plasma lipoprotein lipase and hepatic triglyceride lipase, 197, 339 phospholipase activity of milk lipoprotein lipase, 197, 345. 

Human pancreatic lipase (HPL) alone is inactive in vitro on an emulsified TAG substrate in the presence of supramiceUar concentrations of bile salts such as those found in the small intestine. Bile salts are amphiphilic molecules that bind to the oil-water interface and prevent pancreatic hpase adsorption, and thus hpo-lysis, from occurring [3, 4]. The inhibition by bile salts can, however, be reversed by the specific pancreatic hpase cofactor cohpase [3, 5-7], via the formation of a specific 1 1 hpase-cohpase complex. 

Other biochemists presented evidence that there is a true gastric lipase that in its substrate specificity differs from both lingual and pancreatic lipase. Fritz Schon-heyder and Kirsten Volqvartz of Aarhus determined the substrate specificity of a lipase they found in gastric contents recovered from the stomachs of adult human subjects 25 minutes after the subjects had eaten a meal. Only lower triglycerides, they found, were split while the meal was in the stomach. In vitro the pH optimum of the enzyme depended upon the nature of the substrate, being 5.5 to 5.8 for tri-propein, tributyrin, and tricaproin but 7.0 to 7.9 for tricaprin, trilaurin, and tri-stearin. ... 

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