The surface activity of α-lactalbumin, β-lactoglobulin, and bovine serum albumin

Suttiprasit, Prasert; Krisdhasima, Viwat; McGuire, Joseph

doi:10.1016/0021-9797(92)90146-d

Cited by 126 publications

(31 citation statements)

References 30 publications

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“…The plateau value of 3 Ϯ 0.2 mg/m 2 agrees well with previously reported values. Adsorption of BLA on a platinum surface resulted in a value of 2.9 mg/m 2 (24), and a value of 3.3 mg/m 2 was found for adsorption of BLA on a hydrophobic silicon surface (25). The steep part in the region of low BLA concentration is an indication for high affinity behavior.…”

Section: Resultsmentioning

confidence: 90%

Kinetic and Structural Characterization of Adsorption-induced Unfolding of Bovine α-Lactalbumin

Engel

Mierlo²,

Visser

2002

Journal of Biological Chemistry

103

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Conformational changes of bovine ␣-lactalbumin induced by adsorption on a hydrophobic interface are studied by fluorescence and circular dichroism spectroscopy. Adsorption of bovine ␣-lactalbumin on hydrophobic polystyrene nanospheres induces a non-native state of the protein, which is characterized by preserved secondary structure, lost tertiary structure, and release of calcium. This partially denatured state therefore resembles a molten globule state, which is an intermediate in the folding of bovine ␣-lactalbumin. Stopped-flow fluorescence spectroscopy reveals two kinetic phases during adsorption with rate constants k 1 ϳ 50 s ؊1 and k 2 ϳ 8 s ؊1 . The rate of partial unfolding is remarkably fast and even faster than unfolding induced by the addition of 5.4 M guanidinium hydrochloride to native ␣-lactalbumin. The large unfolding rates exclude the possibility that unfolding of bovine ␣-lactalbumin to the intermediate state occurs before adsorption takes place. Stoppedflow fluorescence anisotropy experiments show that adsorption of bovine ␣-lactalbumin on polystyrene nanospheres occurs within the dead time (15 ms) of the experiment. This shows that the kinetic processes as determined by stopped-flow fluorescence spectroscopy are not affected by diffusion or association processes but are solely caused by unfolding of bovine ␣-lactalbumin induced by adsorption on the polystyrene surface. A scheme is presented that incorporates the results obtained and describes the adsorption of bovine ␣-lactalbumin.Adsorption of proteins on solid/liquid interfaces is a generally occurring phenomenon both in nature and in man-made systems. It is well recognized that proteins undergo conformational changes upon adsorption on solid/liquid interfaces (1-3). Because unfolding of proteins can have a large effect on their function or properties, it is important to increase the knowledge about protein adsorption and about the resulting conformational changes. It is necessary to study not only the conformation of a protein in the adsorbed state but also the kinetics of the adsorption-induced conformational changes. This knowledge will help in controlling wanted or unwanted conformational changes of adsorbed proteins.In this work we focus on the kinetics of adsorption-induced conformational changes of bovine ␣-lactalbumin (BLA) 1 upon interaction with colloidal polystyrene nanospheres. Detailed information on adsorption-induced conformational changes and especially on the kinetics of adsorption-induced conformational changes is sparse. An important reason for this is the experimental difficulty of the presence of an adsorbent, which is usually a solid phase. A few routes have been designed to remove this difficulty. A macroscopic solid/water interface can be used in combination with a reflective technique like ellipsometry or total internal reflection fluorescence (4, 5). In other cases a microscopic system has been used that consists of small particles with diameters ranging from nanometers to micrometers in size (6, 7). The latter syst...

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Section: Resultsmentioning

confidence: 90%

Kinetic and Structural Characterization of Adsorption-induced Unfolding of Bovine α-Lactalbumin

Engel

Mierlo²,

Visser

2002

Journal of Biological Chemistry

103

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“…We assume that the electrostatic repulsion was suppressed by adding 0.1 M NaCl to the SDS solution. Although BSA is not a typical surfactant, it was found that all three obey Langmuir adsorption isotherm with the parameters presented in Table 2 [29,30]. The equilibrium surfactant adsorption, G 0 , and the interfacial tension, |, are related with the surfactant concentration, c 0 , by Langmuir-Szyszkowski adsorption isotherm:…”

Section: Numerical Results and Discussion Of The General Casementioning

confidence: 99%

Surfactants role on the deformation of colliding small bubbles

Valkovska

Danov

Ivanov

1999

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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The mutual approach of two bubbles and the rate of thinning and the deformation of the partially mobile thin liquid film intervening between them is studied. The material properties of the interfaces (surface viscosity, Gibbs elasticity, surface and/or bulk diffusivity) are taken into account. In the normal stress balance at the fluid interfaces we include the contribution of the intermolecular forces. To obtain the liquid velocity and pressure distribution the lubrication approximation is used. From the normal stress boundary condition the first order (with respect to the capillary number) shape function is derived. It provides information on the inversion thickness, at which the curvature in the gap between the drops changes from convex to concave, and the pimple thickness, at which the curvature of the interfaces spontaneously increases due to the action of the attractive intermolecular forces. The analytical and numerical investigations reveal significant influence of the disjoining pressure and the surfactant on both thicknesses. Explanation of the following effects is proposed: (i) increase of the pimple thickness and decrease of the inversion thickness with the increase of the interfacial mobility; (ii) role of the surface viscosity; (iii) role of the van der Waals interaction.

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“…[3][4][5][6] These and other studies have given information on the physicochemical properties that govern the interfacial and rheological properties of whey protein films, and on the correlations that could exist between the interfacial and rheological behaviour of whey proteins and their emulsifying and foaming properties.…”

Section: Introductionmentioning

confidence: 99%

Interfacial properties of fractal and spherical whey protein aggregates

2011

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Fractal and spherical aggregates of whey globular proteins are formed under conditions that coupled heating and shear flow in a plate heat-exchanger at high temperature and for short holding time. Their properties upon adsorption and spreading at the air-water interface have been studied at neutral pH and two subphase conditions. The surface activity of mixtures of aggregates and residual proteins is enhanced and the adsorption behaviour depends strongly on the denatured native-like monomers and the charge screening. After long hours of adsorption, they form a weakly dissipative viscoelastic network, with strong interactions. When spread at the air-water interface, protein aggregates dissociate and form monolayers whose properties are described by scaling laws in the semi-dilute regime. The scaling exponents found in charge-screening subphase conditions correspond to values for polymer in q-conditions, whereas the values determined in long-range repulsion subphase conditions are intermediate between an ideal (q-conditions) chain and a chain in good solvent.

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The surface activity of α-lactalbumin, β-lactoglobulin, and bovine serum albumin

Cited by 126 publications

References 30 publications

Kinetic and Structural Characterization of Adsorption-induced Unfolding of Bovine α-Lactalbumin

Kinetic and Structural Characterization of Adsorption-induced Unfolding of Bovine α-Lactalbumin

Surfactants role on the deformation of colliding small bubbles

Interfacial properties of fractal and spherical whey protein aggregates

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