Shear-induced structural changes and denaturation of bovine immunoglobulin G and serum albumin at different temperatures

Colostrum and milk samples from 60 Holstein–Friesian cows were analysed for concentrations and yields of immunoglobulin G (IgG), β-lactoglobulin (β-lg), α-lactalbumin (α-la) and serum albumin (BSA) throughout the first 16 milkings post partum (8 d of lactation) using a single radial immunodiffusion assay. Concentrations (mg/ml, means±SD) at first milking were IgG 59·8±28·5, β-lg 14·3±4·6, α-la 2·04±0·6, BSA 1·21±0·44. Large variations were recorded for IgG concentrations (15·3–176·2 mg/ml) and yields (0·2–925 g). Cows in their first lactation produced significantly lower concentrations and yields of colostral IgG than cows in later lactations. A colostral yield of IgG below the 100 g required to prevent calf hypo-γ-globulinaemia was found in 18·3% of the cows. The concentrations of IgG, β-lg and BSA dropped abruptly in subsequent milkings and α-la concentration decreased slowly. The mean IgG concentration was <2 mg/ml after eight milkings and <1 mg/ml after fifteen milkings. However, IgG concentration did not differ significantly, at the 1% level, during milkings 11–15. The results were tabulated to make it possible to calculate the excess of whey proteins that would be obtained if early milks were illegally added to the milk supply.

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An All-Atomistic Molecular Dynamics Study to Determine the Structural Importance of Disulfide Bonds in Immunoglobulin G and Bovine Serum Albumin

American Journal of Undergraduate Research ◽

10.33697/ajur.2018.008 ◽

2018 ◽

Vol 15 (1) ◽

Cited By ~ 1

Author(s):

Akshay Mathavan ◽

Akash Mathavan ◽

Michael Fortunato ◽

Coray Colina

Keyword(s):

Molecular Dynamics ◽

Bovine Serum Albumin ◽

Serum Albumin ◽

Immunoglobulin G ◽

Bovine Serum ◽

Disulfide Bonds ◽

Structural Changes ◽

Conformational Stability ◽

The Stability

A fully-atomistic molecular dynamics study was performed to determine the importance of disulfide bonds on the stability of immunoglobulin G (IgG) and bovine serum albumin (BSA).The transferability of a previous prescreening methodology to assess contributions from individual disulfide bonds on conformational stability was tested on both proteins. In IgG, it was apparent that inter-chain and intra-chain disulfide bonds play different roles in maintaining structure, evidenced by clear separation of inter-chain cysteine residues upon cleavage of disulfide bonds. In BSA, a set of double disulfide bonds required both to be broken in order to observe significant structural changes, equivalently seen in a previous study of human serum albumin (HSA), a structurally similar protein. Structural analysis of IgG showed deviations in distances between domains, while analysis of BSA suggested more local structural changes. This work helps confirm the efficacy and reproducibility of the prescreening methodology on both a novel, larger protein such as IgG and a more homologous (to HSA), globular protein such as BSA. The results provide insight into the role of specific disulfide bonds in the stability of IgG and BSA. KEYWORDS: Molecular Dynamics; Atomistic Simulations; Immunoglobulin G; Bovine Serum Albumin; Disulfide Bonds

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BOVINE SERUM ALBUMIN FLUORESCENCE QUENCHING BY TANNIC ACID IN DIMETHYLSULFOXIDE CONTAINING SOLUTIONS

Proceedings of the YSU B: Chemical and Biological Sciences ◽

10.46991/pysu:b/2020.54.2.099 ◽

2020 ◽

Vol 54 (2 (252)) ◽

pp. 99-104

Author(s):

K.R. Grigoryan ◽

H.A. Shilajyan ◽

V.A. Hovhannisyan

Keyword(s):

Bovine Serum Albumin ◽

Fluorescence Quenching ◽

Serum Albumin ◽

Tannic Acid ◽

Bovine Serum ◽

Structural Changes ◽

Different Temperatures ◽

Fluorescence Quenching Mechanism ◽

Bimolecular Quenching ◽

Bsa Interaction

Bovine serum albumin (BSA) interaction with tannic acid (TA) has been studied in dimethylsulfoxide (DMSO) aqueous solutions at different temperatures (293 and 303 K). To find out the fluorescence quenching mechanism of BSA in the presence of TA, the fluorescence data were analyzed according to the modified Stern-Volmer equation based on the approach of the existence of a “sphere of action” (a type of apparent static quenching). The values of apparent static and bimolecular quenching constants were calculated. The effect of DMSO and temperature on BSA–TA interactions is explained on the basis of structural changes in the “sphere of action” of the fluorophore due to the possible inclusion of DMSO molecules in this sphere.

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Heat Treatment Influence on the Corrosion Resistance of a Cu-Al-Fe-Mn Bronze

Revista de Chimie ◽

10.37358/rc.18.5.6260 ◽

2018 ◽

Vol 69 (5) ◽

pp. 1055-1059 ◽

Cited By ~ 1

Author(s):

Mariana Ciurdas ◽

Ioana Arina Gherghescu ◽

Sorin Ciuca ◽

Alina Daniela Necsulescu ◽

Cosmin Cotrut ◽

...

Keyword(s):

Heat Treatment ◽

Corrosion Resistance ◽

Structural Changes ◽

Heating Temperature ◽

Galvanic Corrosion ◽

Cooling Water ◽

Open Circuit ◽

Water Quenching ◽

Heat Treated ◽

Different Temperatures

Aluminium bronzes are exhibiting good corrosion resistance in saline environments combined with high mechanical properties. Their corrosion resistance is obviously confered by the alloy chemical composition, but it can also be improved by heat treatment structural changes. In the present paper, five Cu-Al-Fe-Mn bronze samples were subjected to annealing heat treatments with furnace cooling, water quenching and water quenching followed by tempering at three different temperatures: 200, 400 and 550�C. The heating temperature on annealing and quenching was 900�C. The structure of the heat treated samples was studied by optical and scanning electron microscopy. Subsequently, the five samples were submitted to corrosion tests. The best resistance to galvanic corrosion was showed by the quenched sample, but it can be said that all samples are characterized by close values of open-circuit potentials and corrosion potentials. Concerning the susceptibility to other types of corrosion (selective leaching, pitting, crevice corrosion), the best corrosion resistant structure consists of a solid solution, g2 and k compounds, corresponding to the quenched and 550�C tempered sample.

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