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Lipases are lipolytic enzymes that play a key role in fat metabolism. They are catalysts for the hydrolysis of triacylglycerides, which contribute for major portion of calories to our daily diets. Due to the apolar nature of oils and fats, the oil–water interface is where the control of lipolytic conversion and finally digestion takes place. It might come as a surprise that despite past efforts the interfacial behaviour of lipases is not completely understood. We have undertaken a detailed study of the interfacial behaviour of lipases, their substrates and the products. Our results demonstrate that lipase activity is a function of interfacial composition and changes concurrently with lipolytic conversion. In these cases lipase “inhibition” should be attributed to substrate depletion and not to lipase desorption or denaturation as previously hypothesized. This self-limiting effect through the feedback of interfacial composition to the reaction conditions of the enzyme may open a new way to control lipase catalysis through the interface. To prove our point, we appreciably reduced oil hydrolysis in a model gastro-intestinal system by interfacial engineering of the oil. We anticipate that our findings can contribute in finding new approaches for controlling fat metabolism, which is central to health threats like obesity and diabetes mellitus II and important for the regulation of energy metabolism in general.

Les lipases sont des enzymes lypolytiques jouant un rôle clé dans le métabolisme des graisses [R. Schmid, R. Verger, Angew. Chem., Int. Ed. 37 (1998) 1608]. Ce sont des catalyseurs de l'hydrolyse des triglycerides, lesquels contribuent pour une grande part à notre apport calorique …