Inhibition of pancreatic lipase by mixed micelles of diethyl p-nitrophenyl phosphate and bile salts.
Solubility and Sephadex filtration assays have shown that dissolved diethyl p-nitrophenyl phosphate can be included into bile salt micelles with a partition coefficient of 32 : 1. This inclusion is probably a prerequisite for the organophosphate to inhibit lipase. The essential role played by colipase confirms that the primary step in the inhibition is an interaction of lipase with bile salt containing micelles. Therefore, it appears that the requirements of lipase towards specific substrates and inhibitors are very similar. The inhibition rate strongly depends on the total bile salt concentration and on the micellar concentration of the organophosphate. This effect may be explained, at least qualitatively, by a competition between simple and mixed micelles for the binding of colipase and lipase.
D000818:Animals; D001647:Bile Acids and Salts / Q000494:pharmacology*; D003089:Colipases / Q000494:pharmacology; D008049:Lipase / Q000037:antagonists & inhibitors*; D008823:Micelles; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D010179:Pancreas / Q000201:enzymology; D013552:Swine; D013656:Taurocholic Acid / Q000494:pharmacology; D013657:Taurodeoxycholic Acid / Q000494:pharmacology
D001647:Bile Acids and Salts; D003089:Colipases; D008823:Micelles; D009943:Organophosphorus Compounds; D013657:Taurodeoxycholic Acid; D013656:Taurocholic Acid; D008049:Lipase