The Phase Diagram and the Pressure-Temperature Behavior of Proteins

Heremans, Karel

doi:10.1007/978-94-011-4669-2_23

Cited by 5 publications

(4 citation statements)

References 115 publications

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“…Since then an immense number of phase diagrams have been determined for many proteins, using different unfolding methods such as urea, pH and pressure. For an overview of elliptical phase diagrams determined so far we refer to reviews [1,12]. Such diagrams are not only found for proteins, but also for starch [8], micro-organisms [13] and water-soluble synthetic polymers [14].…”

Section: The Pressure-temperature Stability Diagrammentioning

confidence: 99%

Pressure-induced amorphization in biopolymers

Heremans

Dirix

Meersman

et al. 2002

J. Phys.: Condens. Matter

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Pressure-induced unfolding of proteins in solution shows analogies to the pressure-induced amorphization observed in some inorganic and polymer systems. More specifically, pressure gives rise to conformations that show a strong tendency to form supramolecular aggregates that have some relevance to molecular diseases. Hydrostatic pressure can tune the conformation of the intermediates along the unfolding/aggregation pathway. Pressure can also be used to probe the stability of the aggregate, and thus the interactions that are responsible for it. In particular, we demonstrate that pressure might be an interesting tool to study the fibril formation. Fourier transform infrared spectroscopy reveals the presence of fibril secondary structures other than random coil and intermolecular β-sheet.

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Section: The Pressure-temperature Stability Diagrammentioning

confidence: 99%

Pressure-induced amorphization in biopolymers

Heremans

Dirix

Meersman

et al. 2002

J. Phys.: Condens. Matter

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“…For example, exposure of metmyoglobin to 2 kBar at À16 C resulted in disruption of the protein structure similar to that for the protein which was unfolded at 11 kBar at the room temperature. 89 In another example, a significant (almost 50%) loss of the catalytic activity of carboxypeptidase Y was observed at a moderate pressure of 0.5 kBar at 5 C. 90 The loss of the enzymatic activity was attributed to the hydrostatic pressure promoting cold denaturation of the protein. While pressure-induced unfolding is often reversible, high local protein concentration in the freeze-concentrated solution would increase the probability of protein-protein interaction, which could lead to aggregation in the case of unfolded proteins.…”

Section: Discussionmentioning

confidence: 99%

Freezing of Biologicals Revisited: Scale, Stability, Excipients, and Degradation Stresses

Authelin

Rodrigues

Tchessalov

et al. 2020

Journal of Pharmaceutical Sciences

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Although many biotech products are successfully stored in the frozen state, there are cases of degradation of biologicals during freeze storage. These examples are discussed in the Perspective to emphasize the fact that stability of frozen biologicals should not be taken for granted. Frozen-state degradation (predominantly, aggregation) has been linked to crystallization of a cryoprotector in many cases. Other factors, for example, protein unfolding (either due to cold denaturation or interaction of protein molecules with ice crystals), could also contribute to the instability. As a hypothesis, additional freezingrelated destabilization pathways are introduced in the paper, that is, air bubbles formed on the ice crystallization front, and local pressure and mechanical stresses due to volume expansion during waterto-ice transformation. Furthermore, stability of frozen biologicals can depend on the sample size, via its impact on the freezing kinetics (i.e., cooling rates and freezing time) and cryoconcentration effects, as well as on the mechanical stresses associated with freezing. We conclude that, although fundamentals of freezing processes are fairly well described in the current literature, there are important gaps to be addressed in both scientific foundations of the freezing-related manufacturing processes and implementation of the available knowledge in practice.

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“…On the other side, heat causes a change in the total energy of the protein molecules (Heremans, 1999) but with a lower impact on its density. Thermodynamically, when both the pressure and heat are combined, they can exert synergistic, additive, or antagonistic effects on protein structures depending on location on the pressure–temperature phase diagram (Balasubramaniam et al, 2015; Gupta, Mikhaylenko, Balasubramaniam, & Tang, 2011).…”

Section: Introductionmentioning

confidence: 99%

Thermal and high‐pressure treatment stability of egg‐white avidin in aqueous solution

Dhakal

Shafaat

Balasubramaniam

2020

J Food Process Engineering

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The combined pressure (0.1 and 600 MPa) and thermal (30, 65, 75, 90, and 105°C) treatment effects on the binding properties of egg‐white avidin were investigated using fluorescence spectroscopy titrations with fluorescein‐labeled biotin for various holding times (up to 45 min). Pressure treatment was carried out in a high‐pressure kinetic tester whereas heat treatment was conducted using metal tubes in a temperature‐controlled oil bath. Avidin binding activity and strength decreased by approximately three orders of magnitude with increases in temperature and holding time, while the binding free energy (−52.3 ± 0.47 kJ/mol) remained unaffected by high‐pressure (600 MPa at 30°C) treatment. The thermal inactivation rate constant ranged from 0.009 to 0.793 per min at 65–105°C, 0.1 MPa. Combined pressure (600 MPa)–thermal (65–105°C) treatment reduced the corresponding values by a factor of two to nine, resulting in inactivation rates that ranged from 0.001 to 0.422 per min. Activation energies for avidin inactivation were 120 ± 10 and 149 ± 8 kJ/mol for thermal and combined pressure–thermal treatment, respectively. In conclusion, while heat treatment alone destroyed biotin binding strength of avidin, combined pressure, and heat exhibited antagonistic effects on avidin–biotin binding energies. Practical Applications Heat and pressure can have synergistic, additive, or antagonistic effects on food components. The synergistic effect is important from food safety aspect whereas antagonistic effect is desirable to retain food quality attributes during food processing. The parameters of reaction kinetic models, more specifically rate constant and activation energy can be used to evaluate the interactions of heat and pressure during food processing. Egg‐white avidin has been selected in this study to evaluate the interaction between heat and pressure. Information obtained from this study can be used to preserve egg‐white avidin binding activity for various applications including food formulations, biochemical assays and preservation, due to its enormously high binding ability with biotin.

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The Phase Diagram and the Pressure-Temperature Behavior of Proteins

Cited by 5 publications

References 115 publications

Pressure-induced amorphization in biopolymers

Pressure-induced amorphization in biopolymers

Freezing of Biologicals Revisited: Scale, Stability, Excipients, and Degradation Stresses

Thermal and high‐pressure treatment stability of egg‐white avidin in aqueous solution

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