scholarly journals Application of Glycation in Regulating the Heat-Induced Nanoparticles of Egg White Protein

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 943 ◽  
Author(s):  
Chenying Wang ◽  
Xidong Ren ◽  
Yujie Su ◽  
Yanjun Yang
Keyword(s):  
Thermal Stability ◽  
Protein Concentration ◽  
Thermal Denaturation ◽  
Negative Charge ◽  
Activity Index ◽  
Stability Index ◽  
Egg White ◽  
Egg White Protein ◽  
Neutral Conditions ◽  
Thermal Stability Of

Due to the poor thermal stability of egg white protein (EWP), important challenges remain regarding preparation of nanoparticles for EWP above the denaturation temperature at neutral conditions. In this study, nanoparticles were fabricated from conjugates of EWP and isomalto-oligosaccharide (IMO) after heating at 90 °C for 30 min. Meanwhile, the effects of protein concentration, temperature, pH, ionic strength and degree of glycation (DG) on the formation of nanoparticles from IMO-EWP were investigated. To further reveal the formation mechanism of the nanoparticles, structures, thermal denaturation properties and surface properties were compared between EWP and IMO-EWP conjugates. Furthermore, the emulsifying activity index (EAI) and the emulsifying stability index (ESI) of nanoparticles were determined. The results indicated that glycation enhanced thermal stability and net surface charge of EWP due to changes in the EWP structure. The thermal aggregation of EWP was inhibited significantly by glycation, and enhanced with a higher degree of glycation. Meanwhile, the nanoparticles (<200 nm in size) were obtained at pH 3.0, 7.0 and 9.0 in the presence of NaCl. The increased thermal stability and surface net negative charge after glycation contributed to the inhibition. The EAI and ESI of nanoparticles were increased nearly 3-fold and 2-fold respectively, as compared to unheated EWP.

scholarly journals Succinylation Improves the Thermal Stability of Egg White Proteins

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3783 ◽  
Author(s):  
Dabo He ◽  
Ying Lv ◽  
Qigen Tong
Keyword(s):  
Thermal Stability ◽  
Fluorescence Spectra ◽  
Succinic Anhydride ◽  
Surface Hydrophobicity ◽  
Egg White ◽  
Conformational Structure ◽  
Scanning Calorimetry ◽  
Egg White Protein ◽  
Egg White Proteins ◽  
Thermal Stability Of

Succinylation can improve the thermal stability of various proteins. In this study, succinylated egg white protein (SEWP) samples with different succinylation degrees were prepared by adding various succinic anhydride additives to egg white protein (EWP). The thermal stability of SEWP and the conformational structure under various succinylation degrees were investigated. With the increase in succinylation degree, the turbidity of heated SEWP solution (90 °C for 30 min) markedly declined. The heated SEWP solution with high succinylation degree (37.63%, 66.57%, and 72.37%) was transparent. Moreover, the result of differential scanning calorimetry confirmed that the thermal stability of succinylated EWP increased. The results of intrinsic fluorescence spectra and Fourier-transform infrared spectroscopy illustrate that succinylation changed the conformational structure of EWP. Succinylation increased the electrostatic repulsion and decreased the surface hydrophobicity, and it changed the aggregation morphology of EWP. Cross-linked spherical aggregates of low succinylation degree transformed to thready aggregates of a high succinylation degree. Thus, succinylation improved the thermal stability of EWP.

Effect of osmolytes on the thermal stability of proteins: replica exchange simulations of Trp-cage in urea and betaine solutions

2018 ◽  
Vol 20 (16) ◽  
pp. 11174-11182 ◽  
Author(s):  
Beata Adamczak ◽  
Mateusz Kogut ◽  
Jacek Czub
Keyword(s):  
Thermal Stability ◽  
Molecular Mechanism ◽  
Thermal Denaturation ◽  
Replica Exchange ◽  
Thermal Stability Of ◽  
Denaturation Of Proteins

Although osmolytes are known to modulate the folding equilibrium, the molecular mechanism of their effect on thermal denaturation of proteins is still poorly understood.

Influence of tyrosine nitration on the structure and thermal stability of hen egg white lysozyme

Nitric Oxide ◽  
2012 ◽  
Vol 27 ◽  
pp. S37-S38
Author(s):  
Maria Gómez-Mingot ◽  
Luis A. Alcaraz ◽  
Antonio Donaire ◽  
Jesús Iniesta ◽  
Vicente Montiel
Keyword(s):  
Thermal Stability ◽  
Egg White ◽  
Tyrosine Nitration ◽  
Hen Egg White Lysozyme ◽  
Egg White Lysozyme ◽  
Hen Egg White ◽  
Thermal Stability Of ◽  
Hen Egg

scholarly journals THE THERMAL STABILITY OF RHODOPSIN AND OPSIN

1958 ◽  
Vol 42 (2) ◽  
pp. 259-280 ◽  
Author(s):  
Ruth Hubbard
Keyword(s):  
Thermal Stability ◽  
Thermal Denaturation ◽  
Species Differences ◽  
Activation Energies ◽  
Specific Relationship ◽  
Thermal Bleaching ◽  
Thermal Stability Of ◽  
Cis Isomer

Rhodopsin, the red photosensitive pigment of rod vision, is composed of a specific cis isomer of retinene, neo-b (11-cis), joined as chromophore to a colorless protein, opsin. We have investigated the thermal denaturation of cattle rhodopsin and opsin in aqueous digitonin solution, and in isolated rod outer limbs. Both rhodopsin and opsin are more stable in rods than in solution. In solution as well as in rods, moreover, rhodopsin is considerably more stable than opsin. The chromophore therefore protects opsin against denaturation. This is true whether rhodopsin is extracted from dark-adapted retinas, or synthesized in vitro from neo-b retinene and opsin. Excess neo-b retinene does not protect rhodopsin against denaturation. The protection involves the specific relationship between the chromophore and opsin. Similar, though somewhat less, protection is afforded opsin by the stereoisomeric iso-a (9-cis) chromophore in isorhodopsin. The Arrhenius activation energies (Ea) and entropies of activation (ΔS‡) are much greater for thermal denaturation of rhodopsin and isorhodopsin than of opsin. Furthermore, these values differ considerably for rhodopsins from different species —frog, squid, cattle—presumably due to species differences in the opsins. Heat or light bleaches rhodopsin by different mechanisms, yielding different products. Light stereoisomerizes the retinene chromophore; heat denatures the opsin. Photochemical bleaching therefore yields all-trans retinene and native opsin; thermal bleaching, neo-b retinene and denatured opsin.

scholarly journals Structural insights into protein folding, stability and activity using in vivo perdeuteration of hen egg-white lysozyme

IUCrJ ◽  
2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Joao Ramos ◽  
Valerie Laux ◽  
Michael Haertlein ◽  
Elisabetta Boeri Erba ◽  
Katherine E. McAuley ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Egg White ◽  
Hen Egg White Lysozyme ◽  
Egg White Lysozyme ◽  
Enzymatic Function ◽  
Biophysical Study ◽  
Hen Egg White ◽  
Thermal Stability Of ◽  
Hen Egg

This structural and biophysical study exploited a method of perdeuterating hen egg-white lysozyme based on the expression of insoluble protein in Escherichia coli followed by in-column chemical refolding. This allowed detailed comparisons with perdeuterated lysozyme produced in the yeast Pichia pastoris, as well as with unlabelled lysozyme. Both perdeuterated variants exhibit reduced thermal stability and enzymatic activity in comparison with hydrogenated lysozyme. The thermal stability of refolded perdeuterated lysozyme is 4.9°C lower than that of the perdeuterated variant expressed and secreted in yeast and 6.8°C lower than that of the hydrogenated Gallus gallus protein. However, both perdeuterated variants exhibit a comparable activity. Atomic resolution X-ray crystallographic analyses show that the differences in thermal stability and enzymatic function are correlated with refolding and deuteration effects. The hydrogen/deuterium isotope effect causes a decrease in the stability and activity of the perdeuterated analogues; this is believed to occur through a combination of changes to hydrophobicity and protein dynamics. The lower level of thermal stability of the refolded perdeuterated lysozyme is caused by the unrestrained Asn103 peptide-plane flip during the unfolded state, leading to a significant increase in disorder of the Lys97–Gly104 region following subsequent refolding. An ancillary outcome of this study has been the development of an efficient and financially viable protocol that allows stable and active perdeuterated lysozyme to be more easily available for scientific applications.

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