scholarly journals Characterization of heat-induced aggregates of β-lactoglobulin, α-lactalbumin and bovine serum albumin in a whey protein concentrate environment

2001 ◽  
Vol 68 (3) ◽  
pp. 483-497 ◽  
Author(s):  
PALATASA HAVEA ◽  
HARJINDER SINGH ◽  
LAWRENCE K. CREAMER
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Whey Protein ◽  
Bovine Serum ◽  
Concentrate Solution ◽  
Polyacrylamide Gel Electrophoresis ◽  
Whey Protein Concentrate ◽  
Protein Concentrate ◽  
Two Dimensional ◽  
Β Lactoglobulin

Bovine β-lactoglobulin (β-lg), α-lactalbumin (α-la) and bovine serum albumin (BSA), dispersed in ultrafiltration permeate, that had been prepared from whey protein concentrate solution (100 g/kg, pH 6·8), were heated at 75 °C. The consequent protein aggregation was studied by one-dimensional (1D) and two-dimensional (2D) polyacrylamide gel electrophoresis (PAGE). When 100 g β-lg/kg permeate solution was heated at 75 °C, cooled and examined, large aggregates were observed. These aggregates were partially dissociated in SDS solution to give monomers, disulphide-bonded dimers, trimers and larger aggregates. When mixtures of β-lg and α-la or BSA were heated, homopolymers of each protein as well as heteropolymers of these proteins were observed. These polymer species were also observed in a heated mixture of the three proteins. Two-dimensional PAGE of mixtures demonstrated that these polymers species contained disulphide-bonded dimers of β-lg, α-la and BSA, and 1:1 disulphide-bonded adducts of α-la and β-lg, or BSA. These results are consistent with a mechanism in which the free thiols of heat-treated β-lg or BSA catalyse the formation of a range of monomers, dimers and higher polymers of α-la. It is likely that when whey protein concentrate is heated under the present conditions, BSA forms disulphide-bonded strands ahead of β-lg and that α-la aggregation with β-lg and with itself is catalysed by the heat-induced unfolded BSA and β-lg.

Electrophoretic characterization of the protein products formed during heat treatment of whey protein concentrate solutions

1998 ◽  
Vol 65 (1) ◽  
pp. 79-91 ◽  
Author(s):  
PALATASA HAVEA ◽  
HARJINDER SINGH ◽  
LAWRENCE K. CREAMER ◽  
OSVALDO H. CAMPANELLA
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Whey Protein ◽  
Bovine Serum ◽  
Whey Protein Concentrate ◽  
Protein Concentrate ◽  
Two Dimensional ◽  
One Dimensional ◽  
Monomeric Proteins ◽  
Β Lactoglobulin

Whey protein concentrate (WPC) solutions containing 10, 30, 60 and 120 g dry powder/kg were heated at 75°C and whey protein aggregation was studied by following the changes in the distribution of β-lactoglobulin, α-lactalbumin and bovine serum albumin, using one dimensional and two dimensional PAGE. The one dimensional PAGE results showed that a minimal quantity of large aggregates was formed when 10 g WPC/kg solutions were heated at 75°C for up to 16 min whereas appreciable quantities were formed when 30, 60 and 120 g WPC/kg solutions were similarly treated. The two dimensional PAGE analysis showed that some disulphide-linked β-lactoglobulin dimers were present in heated 10 g WPC/kg solution, but very little was present in heated 120 g WPC/kg solution. By contrast, SDS was able to dissociate monomeric protein from high molecular mass aggregates in heated WPC solution of 120 g/kg but not in 10 g WPC/kg solution heated for 30 min. The rates of loss of native-like and SDS-monomeric β-lactoglobulin, α-lactalbumin and bovine serum albumin during heating increased as the WPC concentration was increased from 10 to 120 g/kg. In 120 g WPC/kg solution heated at 75°C, the amounts of SDS-monomeric β-lactoglobulin in each sample were greater than the quantities of native-like protein. However, in WPC solutions of 10, 30 and 60 g/kg, the differences between the amounts of native-like and SDS-monomeric proteins were slight. The loss of the native-like or SDS-monomeric proteins was consistent with a first or second order reaction. In each case, the apparent reaction rate constant appeared to be concentration-dependent, suggesting a change of aggregation mechanism in the more concentrated solutions. Overall, these results indicate that in addition to disulphide-linked aggregates, hydrophobic aggregates involving β-lactoglobulin, α-lactalbumin and bovine serum albumin were formed in heated WPC solution at high protein concentration, as suggested by model studies using binary mixtures of these proteins.

scholarly journals Investigating resonance energy transfer from protein molecules to van der Waals nanosheets

RSC Advances ◽  
2017 ◽  
Vol 7 (42) ◽  
pp. 26250-26255 ◽  
Author(s):  
Arun Singh Patel ◽  
Praveen Mishra ◽  
Pawan K. Kanaujia ◽  
Syed Shariq Husain ◽  
G. Vijaya Prakash ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Van Der Waals ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Two Dimensional ◽  
Protein Molecules ◽  
2D Nanomaterials

The resonance energy transfer (RET) from tryptophan present in bovine serum albumin (BSA) to two dimensional (2D) nanomaterials has been reported.

Attachment of Listeria innocua to Polystyrene: Effects of Ionic Strength and Conditioning Films from Culture Media and Milk Proteins

2014 ◽  
Vol 77 (3) ◽  
pp. 427-434 ◽  
Author(s):  
GILLES ROBITAILLE ◽  
SÉBASTIEN CHOINIÈRE ◽  
TIMOTHY ELLS ◽  
LOUISE DESCHÈNES ◽  
AKIER ASSANTA MAFU
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bacterial Adhesion ◽  
Bovine Serum ◽  
Biofilm Formation ◽  
Milk Protein ◽  
Milk Proteins ◽  
Listeria Innocua ◽  
Conditioning Films ◽  
Β Lactoglobulin

It is recognized that bacterial adhesion usually occurs on conditioning films made of organic macromolecules absorbed to abiotic surfaces. The objectives of this study were to determine the extent to which milk protein–coated polystyrene (PS) pegs interfere with biofilm formation and the synergistic effect of this conditioning and hypertonic growth media on the bacterial adhesion and biofilm formation of Listeria innocua, used as a nonpathogenic surrogate for Listeria monocytogenes. PS pegs were uncoated (bare PS) or individually coated with whey proteins isolate (WPI), β-lactoglobulin, bovine serum albumin, or tryptic soy broth (TSB) and were incubated in bacterial suspensions in modified Welshimer's broth. After 4 h, the number of adherent cells was dependent on the coating, as follows: TSB (107 CFU/ml) > bare PS > β-lactoglobulin > bovine serum albumin ≈ WPI (104 CFU/ml). The sessile cell counts increased up to 24 h, reaching >107 CFU per peg for all surfaces (P > 0.1), except for WPI-coated PS; this indicates that the inhibitory effects of milk protein conditioning films are transient, slowing down the adhesion process. The 4-h bacterial adhesion on milk protein–coated PS in modified Welshimer's broth supplemented with salt (0 to 10% [wt/vol]) did not vary (P > 0.1), indicating that conditioning with milk proteins was the major determinant for inhibition of bacterial adhesion and that the synergetic effect of salt and milk proteins on adhesion was minimal. Moreover, the presence of 5 to 10% salt significantly inhibited 24-h biofilm formation on the TSB-coated and bare PS, with a decrease of >3 log at 10% (wt/vol) NaCl and almost completely depleted viable sessile bacteria on the milk protein–coated PS.

Über Photoreaktionen und Lumineszenzverhalten von Eosin in wäßrigen Lösungen von β-Lactoglobulin, Rinderserumalbumin und Cystein

1966 ◽  
Vol 21 (4) ◽  
pp. 305-313 ◽  
Author(s):  
G. Reske ◽  
F. Nimmerfall ◽  
J. Stauff
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Amino Acid Residues ◽  
Group Activities ◽  
Photo Oxidation ◽  
Sh Groups ◽  
Spectral Changes ◽  
Sh Group ◽  
Β Lactoglobulin

Interactions of eosin with three different substrates, β-lactoglobuline, bovine serum albumin and cysteine, in aqueous solutions of pH 7 under illumination with light of wavelengths 5200—5400 Å are investigated by changes in absorption spectrum characteristics, SH-group activities and phosphorescence intensities.Only with bovine serum albumin the major part of protein conversion, as shown by spectral changes and diminution of SH-groups due to eosin-sensitized photo-oxidation. In β-lactoglobuline an oxidizing photoreaction occurs, by which eosin is vanishing to the same degree as the protein shows loss of SH-groups and spectral alterations indicating attack on aromatic amino acid residues. There is no red shift of the eosin absorption band at 5170 Å as is observed in solutions of bovine serum albumin, where the intensity of phosphorscence is about 100 fold compared with the intensity obtained by solutions of β-lactoglobulin.The aerobic eosin photoreaction in solutions of β-lactoglobulin is faster than aerobic photobleaching of the dye. Still faster is its bleaching photoreaction with cysteine, which is nearly independent of oxygen.

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