Lipases at interfaces: A review (original) (raw)
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Colloids and Surfaces B: Biointerfaces, 2013
The access to kinetic parameters of lipolytic enzyme adsorption onto lipids is essential for a better understanding of interfacial enzymology and lipase-lipid interactions. The interfacial adsorption of dog gastric lipase (DGL) was monitored as a function of pH and surface pressure (Π), independently from the catalytic activity, using non-hydrolysable 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) monomolecular films. The acid-stable DGL, which initiates fat digestion in the stomach, was then selected because its adsorption kinetics onto hydrophobic solid surfaces were already studied. This gastric lipase was therefore used as a model enzyme to validate both experimental and theoretical approaches. Results show that the adsorption process of DGL at the lipid/water interface depends on a pH-dependent adsorption equilibrium coefficient which is optimum at pH 5.0 (K Ads = 1.7 ±0.05 10 8 M -1 ). K Ads values further allowed an indirect estimation of the molar fraction (Φ E*(%) , mol%) as well as the molecular area (A E* ) of DGL adsorbed onto DLPC monolayer. Based on these data, a model for DGL adsorption onto DLPC monolayer at pH 5.0 is proposed for a surface pressure range of 15 to 25 mN m -1 .
Chemistry and Physics of Lipids, 1996
lnterfacial events during lipid hydrolysis by cutinase are described as measured with the oil-drop tensiometer. A linear relation between enzyme concentration and initial decrease of oil-water interface tension (7o/w) due to lipolytic activity was observed. The amount of hydrolysis products showed a non-linear relation with 7o/w. Hydrolysis is linear with time, even when the area occupied by the fatty acid molecules exceeds the drop surface by a factor 7000. At pH 9.0, fatty acids were found to partition mainly in the oil phase. Formation of calcium soaps and ionization increase the impact of fatty acids on 7o/w without affecting enzyme activity. The presence of fatty acids at the interface, added prior to cutinase, delayed hydrolysis effects on Yo/w. Fatty acids in the water phase almost completely abolished adsorption effects on Yo/w, when the concentration was over the critical micellar concentration (cmc).
International Journal of Biological Macromolecules, 2016
n-Octyl oleate was synthetized by enzymatic esterification reaction of oleic acid and n-octanol. Lipases from porcine pancreatic (PPL), Mucor javanicus (MJL), Candida sp. (CALA), Rhizomucor miehei (RML) and Thermomyces lanuginosus (TLL) were immobilized via interfacial activation on poly-methacrylate particles (PMA) and tested as biocatalysts. Their catalytic properties were determined in the hydrolysis of olive oil emulsion. Among them, TLL-PMA was the biocatalyst that yielded the highest hydrolytic activity (217.8 ± 1.1 IU/g) and immobilized protein loading (37.5 ± 0.4 mg/g). This biocatalyst was also the most active in n-octyl oleate synthesis, thus selected for further studies. Maximum conversion percentage of 95.1 ± 1.3% was observed after 60 min of reaction at 45 • C, 10% m/v of TLL-PMA, and molar ratio oleic acid:n-octanol of 1:1.5 in a solvent-free system. The biocatalyst fully retained its original activity after twelve cycles of reaction of 60 min each. The product was confirmed by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy analysis and their physico-chemical properties were determined according to ASTM standard methods. These results show that the immobilization of an alkalophilic and thermostable lipase (TLL) on PMA particles allowed the preparation of a highly active biocatalyst in hydrolysis and esterification reactions.
Journal of Agricultural and Food Chemistry, 2008
The objective of this study was to investigate the influence of globular protein interfacial cross-linking on the in vitro digestibility of emulsified lipids by pancreatic lipase. 3% (wt/wt) corn oil-in-water emulsions stabilized by either lecithin or-lactoglobulin were prepared (pH 7). A portion of the-lactoglobulin stabilized emulsions was subjected to a heat treatment known to cross-link the adsorbed globular proteins (85°C, 20 min). Pancreatic lipase and bile extract were then added to each emulsion at 37°C (pH 7) and the evolution of the particle charge, particle size, appearance and free fatty acids released were measured over a period of 2 h. The rate and extent of lipid digestion did not differ greatly between lecithin and-lactoglobulin stabilized emulsions, nor did it differ greatly for unheated (BLG-U) or heated (BLG-H)-lactoglobulin stabilized emulsions. For example, the initial rate of lipid digestion was found to be 3.1, 3.4, and 2.3 mM fatty acids s-1 m-2 of lipid surface for droplets stabilized by BLG-U, BLG-H, and lecithin, respectively. Pancreatic lipase was able to adsorb to the droplet surfaces and access the emulsified lipids, regardless of the initial interfacial composition and the fact that some of the original emulsifier appeared to remain at the oil-water interface during digestion. These results help to explain why the human body is so efficient at digesting dietary triacylglycerols.