Foam bovine serum albumin

Synthesis of gold, silver and their alloy nanoparticles using bovine serum albumin as foaming and stabilizing agent. Journal of Materials Chemistry, 15, 5115-5121. 

The protein used was crystalline bovine serum albumin (BSA) obtained from Armour Laboratories. Sodium dodecyl sulfate (SDS) was synthesized from pure dodecyl alcohol and chlorosulfonic acid, recrystallized, and washed with ethyl ether. Sulfuric acid was reagent grade purchased from the J. T. Baker Chemical Co. and used directly. Reagent grade potassium hydroxide purchased from the Mallinkrodt Co. was purified by foaming a concentrated solution, removing the foam, and using the solution directly. 

The assay sample buffer we have used is 0.14 M sodium chloride with 10 mM phosphate, pH 7.0, phenol red at 10 mg/liter, and an inert protein, usually 0.1% gelatin. The protein is included in all samples to minimize adsorptive losses. Gelatin has proved to be most useful because it is free of most potentially cross-reactive proteins that occasionally contaminate some preparations (e.g., luteinizing hormone in crystalline bovine serum albumin) it is free of most small, nonproteinaceous molecules that occasionally contaminate other preparations (e.g., steroids in ovalbumin) it effectively reduces nonspecific adsorption it is inexpensive and it does not cause foaming or create problems with valves on some automatic pipetting equipment. The concentration of phosphate is low and could be increased or supplemented. In effect we accomplish this by including 50 mM EDTA in the buffer used for the first antibody. The phenol red is included to serve as an indicator of dangerous pH shifts upon addition of sample. 

R. W. Schnepf and E. L. Gaden Jr., Foam fractionation of proteins concentration of aqueous solutions of bovine serum albumin, J. Biochem. Microbiol. Tech. Enginr. 1 (1), 1-8 (1959). 

The bovine serum albumin crystals were purchased from the Nutritional Biochemicals Corp., Cleveland, Ohio. A solution was prepared by dissolving about 50 mg protein in a 10-ml solution of 0.5% 1-pentanol (Fisher Scientific Co., Fairlawn, N. J. 07410). The oleic acid and decyl alcohol used in the distillation experiments were purchased from the Hormel Institute, Minnesota. The water for the substrate was distilled from a Stokes still and foamed in a 600-ml medium porosity sintered glass funnel. The foam was removed several times by sweeping the surface to remove surface active impurities. 

Such low-permeable layers can be formed not only on account of high-molecular surfactants. It has been shown in [29] that the adsorption layer permeability of proteins (bovine serum albumin, gamma-globulin) and lauiyl sulphate, determined by loss in weight of the evaporating film, is practically the same. Addition of higher alcohols to alkyl sulphates enhances the foam stability under dry air conditions. When lauryl alcohol was added to dodecyl sulphate, it turned out that the life time of the foam increased by 10 to 20 % at reduced air humidity. Note that this effect is more pronounced at maximum undersaturation of air by water vapours. 

Effect of pH on Some Film and Foaming Properties of Bovine Serum Albumin... 

Bovine serum albumin (BSA), a globular protein, is often applied as a model protein for foam formation. The surface tension of BSA solutions as a function of time indicates that, depending on the BSA concentration, it can take 15 to 20 h to attain an equihbrium surface tension which is independent of the BSA concentration. The coagulation rates are shght and the loss of native protein in the svuface film due to adsorption and denaturation is compensated by the quick and continuous diffusive transport of native protein to the surface. Therefore, the critical micelle concentration (CMC) and Ocmc can be evaluated from these measmements. 

FIGURE 4. Foam cell formation The effect of ascorbic acid and copper concentration. The culture of murine peritoneal macrophages with artificial lipoproteins composed of cholesteryl linoleate and bovine serum albumin (BSA) leads to foam cell formation which can be monitored by measuring the intracellular accumulation of the fluorescent lipopigment, ceroid. The effect of ascorbic acid (0-3 mM) and Cu (II) concentration (O-I xM) is shown. Reprinted with permission (Hunt et ai, 1992a). 

The whipping properties of dried egg white can be improved by the addition of whey proteins, casein and bovine serum albumin. The foaming ability is also increased by weak proteolysis and partial hydrolysis of the oligosaccharides in the glycoproteins by treatment with amylases. 

Nemeth et al. [132] also report the effect of polyethoxy-polypropoxy block copolymers (EO .PO .EO , where m = 33 and 2.5 foam behavior of a protein—bovine serum albumin (BSA). These block copolymers reduced both the foamability and stability of the foam of BSA solutions at temperatures below the relevant cloud point where the solution was homogeneous. Filtration of the mixed solutions at the tanperature of these foam experiments produced essentially no enhanconent of foamability or foam stability. However, the filtration was done before foam generation so that the possibility of the decomposition of any putative metastable state during foam generation was not examined. Unlike with the PDMS-EOPO copolymer/Triton X-100 system, the possibility that antifoam effects at temperatnres above a measured cloud point for this EO-PO-EO -i- BSA system, which could be eliminated by removal of the relevant conjugate phase, was not explored. 

Foam fractionation is a relatively inexpensive technique for protein separation. Most studies in the literature are, however, experimental and very few report on industrial appUcations. Among other appUcations, foam liaclionation has been used to separate wheat flour proteins, ovalbumin, lysozyme, egg albumin, milk proteins (e.g., beta-casein, bovine lactoferrin, bovine serum albumin, alpha-lactalbumin, and beta-lactoglobulin) and potato protein from potato juice waste water after starch extraction (Weijenberg et al., 1978 Keller et al., 1997 Hossain and Fenton, 1998 Brown et al., 1999 Wang and Liu, 2(X)3 Wang etal., 2009). 

Gas flow requirements to produce stable foams were found to be lower for bovine serum albumin and beta-lactoglobulin, which had greater surface activity compared to beta-casein and alpha-lactalbumin, and the enrichment factor and percentage volume loss in foam were also higher for the former proteins (Hossain and Fenton, 1998). 

For immobilisation of chloroplasts into foams in situ the urethane prepolymer Hypol 5000 warmed up to 50° was poured into a glass vial containing an equal volume of a suspension of chloroplasts in 50mM HEPES buffer pH 7.5 (containing 0.2% bovine serum albumin) kept in ice. A sponge of polyurethane embedding the chloroplast membranes was formed within 15 min. For coimmobilization of chloroplasts and catalyst the latter was added to the chloroplast suspension before addition of Hypol. 

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