Surface behaviour of bile salts and tetrahydrolipstatin at air/water and oil/water interfaces.
The surface behaviour of two bile salts, sodium deoxycholate (NaDC) and sodium taurodeoxycholate (NaTDC), as well as that of tetrahydrolipstatin (THL), a potent gastrointestinal lipase inhibitor, was studied at air/water and oil/water interfaces, using interfacial tensiometry methods. The surface behaviour of NaDC and NaTDC was comparable at both oil/water and air/water interfaces. A fairly compact interfacial monolayer of bile salts is formed well below the critical micellar concentration (CMC) and can help to explain the well-known effects of bile salts on the kinetic behaviour of pancreatic lipases. Using the Wilhelmy plate technique, the surface pressure-molecular area curves recorded with THL at the air/water interface showed a collapse point at a surface pressure of 24.5 mN.m(-1), corresponding to a molecular area of 70 A(2). Surprisingly, using the oil drop method, a limiting molecular area of 160 A(2) was found to exist at the oil/water interface. On the basis of the above data, space-filling models were proposed for bile salts and THL at air/water and oil/water interfaces.
Tiss
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Laboratoire de Lipolyse Enzymatique, UPR 9025 du CNRS, 31 chemin Joseph-Aiguier, 13402, Cedex 20, Marseille, France.
Ransac
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S
Lengsfeld
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Hadvàry
P
P
Cagna
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Verger
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R
D000388:Air; D001647:Bile Acids and Salts / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D007783:Lactones / Q000737:chemistry* / Q000494:pharmacology; D008049:Lipase / Q000037:antagonists & inhibitors*; D008823:Micelles; D009821:Oils; D000077403:Orlistat; D013499:Surface Properties; D014867:Water
D001647:Bile Acids and Salts; D004791:Enzyme Inhibitors; D007783:Lactones; D008823:Micelles; D009821:Oils; D014867:Water; D000077403:Orlistat; D008049:Lipase