Effects of Surfactants on Lipase Structure, Activity, and Inhibition

Abstract

Lipase inhibitors are the main anti-obesity drugs prescribed these days, but the complexity of their mechanism of action is making it difficult to develop new molecules for this purpose. The efficacy of these drugs is known to depend closely on the physico-chemistry of the lipid-water interfaces involved and on the unconventional behavior of the lipases which are their target enzymes. The lipolysis reaction which occurs at an oil-water interface involves complex equilibria between adsorption-desorption processes, conformational changes and catalytic mechanisms. In this context, surfactants can induce significant changes in the partitioning of the enzyme and the inhibitor between the water phase and lipid-water interfaces. Surfactants can be found at the oil-water interface where they compete with lipases for adsorption, but also in solution in the form of micellar aggregates and monomers that may interact with hydrophobic parts of lipases in solution. These various interactions, combined with the emulsification and dispersion of insoluble substrates and inhibitors, can either promote or decrease the activity and the inhibition of lipases. Here, we review some examples of the various effects of surfactants on lipase structure, activity and inhibition, which show how complex the various equilibria involved in the lipolysis reaction tend to be.

Modulating absorption and postprandial handling of dietary fatty acids by structuring fat in the meal: a randomized crossover clinical trial

“…This is consistent with reports of enhanced FA absorption when a simple bolus of vegetable oil was emulsified in humans (27) and rodents (14,15,28). One explanation was that the surface area of our emulsion was w70,000 times greater for lipases than for spread fat, which is reported to enhance lipolysis and absorption (29). Enteral emulsions of different droplet sizes, w1 compared with w10 mm (14.5-fold difference in fat surface area), were shown to result in small differences only in postprandial FIGURE 3.…”

“…This could have favored lipid emptying in the upper intestine and a rapid rise of plasma triacylglycerols in rats. Our study also provides a proof of concept that the effects of fat structure in the meal can occur in a real mixed meal, whereas previous studies used an oil or emulsion bolus fed orally or intragastrically (17,29). Regarding emulsifier type, our fat was emulsified by the proteins naturally present in skim milk.…”

Novel extracellular medium-chain-length polyhydroxyalkanoate depolymerase from Streptomyces exfoliatus K10 DSMZ 41693: a promising biocatalyst for the efficient degradation of natural and functionalized mcl-PHAs

“…Remarkably, a significant enhancement in the presence of low concentrations of nonionic and anionic detergents was observed in PhaZ Sex2 . Similarly to lipases, detergents can improve the availability of the substrate by promoting emulsification or triggering protein conformational changes, which will improve the accessibility of the active site (Delorme et al 2011). Higher detergent concentrations markedly decreased the enzyme activity.…”

Partial purification and biochemical characterization of extracellular lipase from Azospirillum sp. JG3 bacteria

“…According to [27], SDS acts upon the disulfide linkage of the enzyme and so causes inactivation of the enzyme. Commercial detergent decreases the activity of lipase possibly by interacting with the hydrophobic group of an enzyme that alters the structure of three-dimensional conformation [28]. To overcome the inhibitory effect of surfactants and detergents to the activity of lipase can be done by immobilization of the lipase enzyme.…”