scholarly journals Chemical fractionation of caseins by differential precipitation: influence of pH, calcium addition, protein concentration and temperature on the depletion in α‐ and β‐caseins

2019 ◽  
Vol 55 (2) ◽  
pp. 542-552 ◽  
Author(s):  
Loïc Kern ◽  
Olivier Fabre ◽  
Joël Scher ◽  
Jeremy Petit
Keyword(s):  
Protein Concentration ◽  
Chemical Fractionation ◽  
Calcium Addition ◽  
Influence Of Ph ◽  
Differential Precipitation

scholarly journals Bridging interactions of proteins with silica nanoparticles: The influence of pH, ionic strength and protein concentration

Soft Matter ◽  
2014 ◽  
Vol 10 (5) ◽  
pp. 718-728 ◽  
Author(s):  
Bhuvnesh Bharti ◽  
Jens Meissner ◽  
Sabine H. L. Klapp ◽  
Gerhard H. Findenegg
Keyword(s):  
Ionic Strength ◽  
Silica Nanoparticles ◽  
Protein Concentration ◽  
Influence Of Ph

Studies on Characteristics and Adsorption of BSA on Hydrogel Biomaterials

2007 ◽  
Vol 330-332 ◽  
pp. 901-904
Author(s):  
G.X. Tan ◽  
Ying De Cui ◽  
Ying Jun Wang
Keyword(s):  
Ionic Strength ◽  
Bovine Serum Albumin ◽  
Chemical Stability ◽  
Contact Lens ◽  
Bovine Serum ◽  
Protein Concentration ◽  
Radical Copolymerization ◽  
Vinyl Pyrrolidone ◽  
Equilibrium Water Content ◽  
Influence Of Ph

Hydrogel biomaterials were synthesized by radical copolymerization of N-vinyl pyrrolidone (NVP) and 2-hydroxyethylmathacrylate (HEMA), with azobisisobutyronitrile (AIBN) as an initiator, reacting at 60~70°C for 24 hours, which were designed as contact lens due to the good chemical stability and high biocompatibility. The absorbency of bovine serum albumin (BSA) was measured by the ultraviolet spectrophotometer. The influence of pH, initial protein concentration and ionic strength were investigated in detail. The results showed that the absorption of protein on hydrogel biomaterials increased with the immersing time increasing, and was stable during 4 days. The absorption of protein on hydrogel increased with the equilibrium water content increasing. The protein absorption on hydrogels reduced the permeability of the oxygen of the biomaterials.

UV Detection and Avoidance of Protein in Basella alba leaf Mucilage Polysaccharide by differential precipitation

2021 ◽  
pp. 3093-3096
Author(s):  
Arvind P ◽  
Priyadarshini S ◽  
Duraiswamy B ◽  
Dhanabal SP ◽  
Ramu G
Keyword(s):  
Hydrochloric Acid ◽  
Protein Concentration ◽  
Lower Percentage ◽  
Uv Spectrum ◽  
Experimental Conditions ◽  
Ph Adjustment ◽  
Basella Alba ◽  
Residual Protein ◽  
Before And After ◽  
Differential Precipitation

Objective: In the aim of refining mucilage polysaccharide extracted from the leaf of Basella alba, extraction and differential precipitation of the protein content was studied. This was attempted by pH adjustment by adding Trichloroacetic acid (TCA) and Hydrochloric acid (HCl). Materials and Methods: The presence of residual protein before and after deproteinization in the polysaccharide solution was detected by UV spectrum analysis. The % polysaccharide, % polysaccharide loss, protein concentration and the deproteinization efficiency were studied as comparative indices to evaluate the precipitation experimental conditions using pH adjustment. Results: The result showed that 10% w/v TCA precipitated over 80% of the protein when the pH of the aqueous polysaccharide solution was 3. Discussion: TCA was proved to be superior to hydrochloric acid as evidenced by the highest deproteinization efficiency (83.3%). The polysaccharides of all the extracted solutions obtained were identified with only slight variations in percentage. The Hcl method excelled over the TCA method in obtaining polysaccharides with little lower percentage of polysaccharide loss (13.94 %). Conclusion: The TCA method will offer a room for deproteinization of polysaccharides if optimization is studied.

The influence of pH, protein concentration and calcium ratio on the formation and structure of nanotubes from partially hydrolyzed bovine α-lactalbumin

Soft Matter ◽  
2019 ◽  
Vol 15 (24) ◽  
pp. 4787-4796 ◽  
Author(s):  
XiaoLu Geng ◽  
Jacob Judas Kain Kirkensgaard ◽  
Lise Arleth ◽  
Jeanette Otte ◽  
Richard Ipsen
Keyword(s):  
Protein Concentration ◽  
Reaction Conditions ◽  
Food Grade ◽  
Transparent Gels ◽  
Almost All ◽  
Influence Of Ph ◽  
Β Sheet

A food grade protein was shown to self-assemble into nanotubes at almost all the conditions applied in this study with similar dimension and the same β-sheet motif. The reaction conditions affect the formation of physical states including transparent, semi-transparent, or non-transparent gels, or sediments.

Influence of pH on the release and chemical fractionation of heavy metals in sediment from a suburban drainage stream in an arid mine-based oasis

2017 ◽  
Vol 17 (10) ◽  
pp. 2524-2536 ◽  
Author(s):  
Fei Zang ◽  
Shengli Wang ◽  
Zhongren Nan ◽  
Jianmin Ma ◽  
Yu Wang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Chemical Fractionation ◽  
Influence Of Ph

Influence of pH value on microstructure of oil-in-water emulsions stabilized by chickpea protein flour

2018 ◽  
Vol 24 (7) ◽  
pp. 555-563 ◽  
Author(s):  
Manuel Felix ◽  
Nadia Isurralde ◽  
Alberto Romero ◽  
Antonio Guerrero
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Protein Concentration ◽  
Ph Value ◽  
Droplet Size Distribution ◽  
Laser Scanning Microscopy ◽  
Plant Proteins ◽  
Small Amplitude Oscillatory Shear ◽  
Oil In Water ◽  
Influence Of Ph

Food industry is highly interested in the development of healthier formulations of oil-in-water emulsions, stabilized by plant proteins instead of egg or milk proteins. These emulsions would avoid allergic issues or animal fat. Among other plant proteins, legumes are a cost-competitive product. This work evaluates the influence of pH value (2.5, 5.0 and 7.5) on emulsions stabilized by chickpea-based emulsions at two different protein concentration (2.0 and 4.0 wt%). Microstructure of chickpea-based emulsions is assessed by means of backscattering, droplet size distributions and small amplitude oscillatory shear measurements. Visual appearances as well as confocal laser scanning microscopy images are obtained to provide useful information on the emulsions structure. Interestingly, results indicate that the pH value and protein concentration have a strong influence on emulsion microstructure and stability. Thus, the system which contains protein surfaces positively charged shows the highest viscoelastic properties, a good droplet size distribution profile and non-apparent destabilization phenomena. Interestingly, results also reveal the importance of rheological measurements in the prediction of protein interactions and emulsion stability since this technique is able to predict destabilization mechanisms sooner than other techniques such as backscattering or droplet size distribution measurements.

scholarly journals INFLUENCE OF pH AND OF CERTAIN OTHER CONDITIONS ON THE STABILITY OF THE INFECTIVITY AND RED CELL AGGLUTINATING ACTIVITY OF INFLUENZA VIRUS

1944 ◽  
Vol 80 (6) ◽  
pp. 507-520 ◽  
Author(s):  
Gail Lorenz Miller
Keyword(s):  
Influenza Virus ◽  
Phosphate Buffer ◽  
Protein Concentration ◽  
Biological Properties ◽  
Virus Protein ◽  
Swine Virus ◽  
Alkaline Side ◽  
The Stability ◽  
Different Strains ◽  
Influence Of Ph

A study has been made of the pH stability of centrifugally purified strains of influenza virus with respect to the biological properties of mouse infectivity and chicken red blood cell agglutinating activity. Observations also were made on the importance of composition of buffer, temperature of storage, and concentration of virus protein to the stability of the virus. When tested for stability at a protein concentration of 0.1 mg. per cc. in phosphate buffer, the infectivity of PR8 virus was found to be most stable at pH 6.5–7; the swine virus, at pH 7–7.9; and the Lee strain, at a pH of 7.9 or higher. The CCA activity of the PR8 virus in phosphate buffer was most stable at pH 7, that of the swine virus at pH 7–8, and that of the Lee virus at a pH greater than 9. Furthermore, the Lee virus was much less stable in dilute solution in phosphate buffer, even under optimum conditions of pH, than either the PR8 or swine strains. The different strains of influenza virus were found to possess certain characteristics in common. They lost infectivity and CCA activity on the acid side of optimum pH conditions much more rapidly than on the alkaline side. Under suitable conditions of buffer and pH, the infectivity decreased while the CCA activity remained unchanged. In general, the rate of loss in infectivity was greater than the rate of loss in CCA activity. When tests of stability were carried out at a protein concentration of 0.1 mg. per cc. in a composite phosphate-glycine-NaCl buffer, the virus strains showed less marked differences and possessed much higher stabilities of CCA activity and infectivity than when stored at the same concentration in phosphate buffer alone. Under the modified conditions, all three viruses possessed maximum stabilities of CCA activity and infectivity at pH 7–8 with the exception of the PR8 virus whose infectivity appeared more stable at pH 7 than at pH 8. In detailed experiments with the Lee virus, it was found that the infectivity and CCA activity of this strain at pH 7 and at a protein concentration of 0.1 mg. per cc. were maintained best in the composite phosphate-glycine-NaCl buffer, less well in a buffer containing glycine and NaCl, and least well in phosphate buffer alone. In tests with PR8 virus, the activity was found to be much more stable at 4° C. than at 23° C. When stored at a concentration of 2 mg. per cc. at 4° C. in phosphate buffer at pH 7, the PR8 and Lee strains were found to be much more stable than when stored at the concentration of 0.1 mg. per cc. At the higher concentration, no significant losses in either infectivity or CCA activity were observed over a period of 2 months.

Effect of protein concentration, pH, lactose content and pasteurization on thermal gelation of acid caprine whey protein concentrates

2005 ◽  
Vol 72 (1) ◽  
pp. 34-38 ◽  
Author(s):  
Stéphanie Bordenave-Juchereau ◽  
Bruno Almeida ◽  
Jean-Marie Piot ◽  
Frédéric Sannier
Keyword(s):  
Whey Protein ◽  
Protein Concentration ◽  
Chloride Content ◽  
Raw Milk ◽  
Whey Protein Concentrate ◽  
Pasteurized Milk ◽  
Thermal Gelation ◽  
90 C 30 ◽  
C 30 ◽  
Influence Of Ph

The influence of pH (4·5–6·5), sodium chloride content (125–375 mM), calcium chloride content (10–30 mM), protein concentration (70–90 g/l) and lactose content on the gel hardness of goat whey protein concentrate (GWPC) in relation to the origin of the acid whey (raw or pasteurized milk) was studied using a factorial design. Gels were obtained after heat treatment (90 °C, 30 min). Gel hardness was measured using texture analyser. Only protein concentration and pH were found to have a statistically significant effect on the gel hardness. An increase in the protein concentration resulted in an increase in the gel hardness. GWPC containing 800 g/kg protein formed gels with a hardness maximum at the pHi, whereas GWPC containing 300 g/kg protein did not form true gels. Whey from pasteurized milk formed softer gels than whey from raw milk. A high lactose content (≈360 g/kg) also reduced the gelation performance of GWPC.

Albumin-Induced Endocytic Vacuoles in Tetrahymena Pyrijormis

1975 ◽  
Vol 33 ◽  
pp. 694-695
Author(s):  
L. J. Brenner ◽  
D. G. Osborne ◽  
B. L. Schumaker
Keyword(s):  
Electron Microscopy ◽  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Protein Concentration ◽  
Tetrahymena Pyriformis ◽  
Sequence Of Events ◽  
Cytoplasmic Bodies ◽  
Food Vacuoles ◽  
Mouse Ascites ◽  
Normal Human

Exposure of the ciliate, Tetrahymena pyriformis, strain WH6, to normal human or rabbit sera or mouse ascites fluids induces the formation of large cytoplasmic bodies. By electron microscopy these (LB) are observed to be membrane-bounded structures, generally spherical and varying in size (Fig. 1), which do not resemble the food vacuoles of cells grown in proteinaceous broth. The possibility exists that the large bodies represent endocytic vacuoles containing material concentrated from the highly nutritive proteins and lipoproteins of the sera or ascites fluids. Tetrahymena mixed with bovine serum albumin or ovalbumin solutions having about the same protein concentration (7g/100 ml) as serum form endocytic vacuoles which bear little resemblance to the serum-induced LB. The albumin-induced structures (Fig. 2) are irregular in shape, rarely spherical, and have contents which vary in density and consistency. In this paper an attempt is made to formulate the sequence of events which might occur in the formation of the albumin-induced vacuoles.

Monoamine Oxidase and Other Mitochondrial Enzymes in Density Subpopulations of Human Platelets

1988 ◽  
Vol 59 (01) ◽  
pp. 029-033 ◽  
Author(s):  
K G Chamberlain ◽  
D G Penington
Keyword(s):  
Monoamine Oxidase ◽  
Protein Concentration ◽  
Close Correlation ◽  
Human Platelets ◽  
Mitochondrial Enzymes ◽  
Density Fractions ◽  
Percoll Gradients ◽  
Normal Human ◽  
The Mean ◽  
Very High

SummaryNormal human platelets have been separated according to density on continuous Percoll gradients and the platelet distribution divided into five fractions containing approximately equal numbers of platelets. The mean volumes and protein contents of the platelets in each fraction were found to correlate positively with density while the protein concentration did not differ significantly between the fractions. Four mitochondrial enzymes (monoamine oxidase, glutamate dehydrogenase, cytochrome oxidase and NADP-dependent isocitrate dehydrogenase) were assayed and their activities per unit volume were found to increase in a very similar monotonie fashion with platelet density. When MAO and GDH were assayed on the same set of density fractions the correlation between the two activities was very high (r = 0.94–1.00, p <0.001) and a similar close correlation was found between MAO and ICDH. The results support the hypothesis that high density platelets either have a higher concentration of mitochondria or have larger mitochondria than low density platelets.

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