Effect of polyol osmolytes on ΔGD, the Gibbs energy of stabilisation of proteins at different pH values

Haque, Inamul; Singh, Rachna; Moosavi-Movahedi, Ali Akbar; Ahmad, Faizan

doi:10.1016/j.bpc.2005.04.004

Cited by 91 publications

(68 citation statements)

References 37 publications

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“…However, under extremely high alkaline conditions (beyond pH 12) the solubility decreased notably. This could be a result of significant protein denaturation and clustering, rendering the proteins insoluble (Haque et al, 2005). The variation in protein recovery was only about 10% in the entire pH range of 6-12, although the trend was irregular.…”

Section: Protein Solubility Curvementioning

confidence: 99%

Optimization of Protein Extraction from Spirulina platensis to Generate a Potential Co-Product and a Biofuel Feedstock with Reduced Nitrogen Content

et al. 2015

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The current work reports protein extraction from Spirulina platensis cyanobacterial biomass in order to simultaneously generate a potential co-product and a biofuel feedstock with reduced nitrogen content. S. platensis cells were subjected to cell disruption by high-pressure homogenization and subsequent protein isolation by solubilization at alkaline pH followed by precipitation at acidic pH. Response surface methodology was used to optimize the process parameters -pH, extraction (solubilization/precipitation) time and biomass concentration for obtaining maximum protein yield. The optimized process conditions were found to be pH 11.38, solubilization time of 35 min and biomass concentration of 3.6% (w/w) solids for the solubilization step, and pH 4.01 and precipitation time of 60 min for the precipitation step. At the optimized conditions, a high protein yield of 60.7% (w/w) was obtained. The protein isolate (co-product) had a higher protein content [80.6% (w/w)], lower ash [1.9% (w/w)] and mineral content and was enriched in essential amino acids, the nutritious γ-linolenic acid and other high-value unsaturated fatty acids compared to the original biomass. The residual biomass obtained after protein extraction had lower nitrogen content and higher total non-protein content than the original biomass. The loss of about 50% of the total lipids from this fraction did not impact its composition significantly owing to the low lipid content of S. platensis (8.03%).

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Section: Protein Solubility Curvementioning

confidence: 99%

Optimization of Protein Extraction from Spirulina platensis to Generate a Potential Co-Product and a Biofuel Feedstock with Reduced Nitrogen Content

et al. 2015

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“…Recent studies on thermodynamics parameters have also shown that while polyols could increase the Tm of model proteins in direct relationship with their concentrations, they manifest an effect on the Gibbs energy of stabilization of proteins at lower pHs (with no effect at neutral pH) against thermal denaturation [93,94]. Individually, polyols have also been studied with regard to their specific effect on proteins, sometimes with various effects.…”

Section: Polyolsmentioning

confidence: 99%

Protein-Protein interactions leading to aggregation: Perspectives on mechanism, significance and control

Ebrahim‐Habibi

Morshedi

Rezaei‐Ghaleh

et al. 2010

JICS

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Protein aggregates, whether amorphous or structured (amyloid), have attracted much attention in recent years and despite extensive efforts, the mechanism of their formation is poorly understood. While "natural" aggregation (polymerization) of monomers could improve the biological function of some proteins, it is usually the darker side of this phenomenon which is discussed in many studies: deleterious aggregation that could lead to loss of biological activity under in vitro conditions or cause misfolding diseases. In this review, protein aggregation has been overviewed, starting from some general concepts involved in its formation, followed by mentioning studies aimed at elucidation of its kinetics and mechanism, or characterization of intermediates that would be aggregation-prone, and finally, reporting some of the studies related to the design of methods that would control the process. Similarly, amyloid aggregates have been defined, and current methods used in their characterization have been briefly described, with an emphasis on in silico studies. Finally, identification and design of such molecules which may be effective in control of this process is discussed.

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“…The DG D -value thus obtained has a large error, which increases with an increase in T m (the midpoint of thermal denaturation) caused by the presence of compatible osmolytes. For instance, if values of T m (midpoint of denaturation), DH m (enthalpy change at T m ) and DC p (constant pressure -heat capacity change) are 86.5 -C, 564.0 T 40 kJ mol À 1 and 6.77 T 0.54 kJ mol À 1 K À 1 [9], respectively, the DG D -is estimated with an error of 17% (DG D -= 58.62 T 9.86 kJ mol À 1 ) and this error increases with the rise in T m due to the presence of osmolyte. These considerations cast doubt on our earlier conclusions regarding the effect of polyols on DG D -of proteins [9].…”

Section: Introductionmentioning

confidence: 99%

“…For instance, if values of T m (midpoint of denaturation), DH m (enthalpy change at T m ) and DC p (constant pressure -heat capacity change) are 86.5 -C, 564.0 T 40 kJ mol À 1 and 6.77 T 0.54 kJ mol À 1 K À 1 [9], respectively, the DG D -is estimated with an error of 17% (DG D -= 58.62 T 9.86 kJ mol À 1 ) and this error increases with the rise in T m due to the presence of osmolyte. These considerations cast doubt on our earlier conclusions regarding the effect of polyols on DG D -of proteins [9]. We thought it would be worthwhile to measure DG D -of lysozyme and ribonuclease-A (RNase-A) using a more accurate method, i.e., from the guanidinium chloride (GdmCl)-induced denaturation at 25 -C and under the solvent conditions (polyols and pH values) used in thermal denaturation studies of these proteins [9].…”

Section: Introductionmentioning

confidence: 99%

“…The mechanism of osmolyte compatibility and osmolyte-induced stability has, therefore, attracted considerable attention in recent years [5]. We have been interested for some time in understanding the thermodynamic basis of stabilization of proteins by naturally occurring osmolytes [6][7][8][9][10]. The main conclusions of our studies are that compatible osmolytes do not perturb the protein denaturation equilibrium, N (native) state 6 D (denatured) state near physiological pH (6.0-7.0) and temperature (25 -C), and they stabilize proteins at lower pH values by shifting the denaturation equilibrium toward the left.…”

Section: Introductionmentioning

confidence: 99%

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Stability of proteins in the presence of polyols estimated from their guanidinium chloride-induced transition curves at different pH values and 25 °C

Haque

Islam

Singh

et al. 2006

Biophysical Chemistry

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Effect of polyol osmolytes on ΔGD, the Gibbs energy of stabilisation of proteins at different pH values

Cited by 91 publications

References 37 publications

Optimization of Protein Extraction from Spirulina platensis to Generate a Potential Co-Product and a Biofuel Feedstock with Reduced Nitrogen Content

Optimization of Protein Extraction from Spirulina platensis to Generate a Potential Co-Product and a Biofuel Feedstock with Reduced Nitrogen Content

Protein-Protein interactions leading to aggregation: Perspectives on mechanism, significance and control

Stability of proteins in the presence of polyols estimated from their guanidinium chloride-induced transition curves at different pH values and 25 °C

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