Protein denaturation by urea: Slash and bond

Rossky, Peter J.

doi:10.1073/pnas.0809224105

Cited by 136 publications

(117 citation statements)

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“…Urea is found capable to denature proteins by binding onto the protein peptide backbone via hydrogen bonding to the polar moieties of proteins [15][16][17]. It is also reported elsewhere [18] that urea readily promotes solvation of protein hydrophobic groups whereby partial solubility of hydrocarbon was seen in the presence of aqueous urea.…”

Section: Results and Discussion Protein Contents And Zeta Potentialsmentioning

confidence: 94%

“…It is hoped that this figure will clarify and demonstrate the mechanism of how the rubber particles assemble during deproteinisation process using urea and SDS. The removal of proteins from the surface of rubber particles by urea may create weakens hydrophobic forces of protein layer [15,22], hence resulting to the merging of rubber particles with adjacent particles (Figure 4a). However, as mentioned earlier, it is uncertain whether the particles are permanently attached together or just in contact with adjacent particle.…”

Section: Results and Discussion Protein Contents And Zeta Potentialsmentioning

confidence: 99%

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Zeta Potential and Environmental Scanning Electron Microscopy Analysis in Deproteinisation of Natural Rubber Latex

Abdullah¹

2016

MJAS

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This paper describes the effect of protein denaturants namely, urea and sodium dodecyl sulphate (SDS) in the deproteinisation of high ammonia natural rubber latex (HA-NRL). It had been shown that latex proteins were reduced more in the presence of urea alone (48%) than in the presence of SDS (18%). The synergistic effect when both urea and SDS were used in the latex deproteinisation attributed to the higher protein removal efficacy (55%). Higher zeta potential value was observed when only SDS was used, suggesting higher colloidal stability. Environmental Scanning Electron Microscopy (ESEM) revealed that without SDS, the use of urea single-handedly in the deproteinisation process promoted aggregation of latex particles, possibly due to the dismissal of latex proteins which helped to stabilise latex colloidal. Thus, it is most likely that urea serves as a protein unfolding agent during latex deproteinisation process, while SDS functions as a latex stabiliser with no significant effects on latex proteins discharge.Keywords: urea, sodium dodecyl sulphate, deproteinisation, zeta potential, environmental scanning electron microscopy Abstrak Kertas kerja ini menghuraikan kesan bahan-bahan pengubah sifat protein iaitu urea dan natrium dodekil sulfat (NDS) dalam penyahprotein lateks getah asli tinggi ammonia (HA-NRL). Ia telah menunjukkan bahawa protein lateks lebih banyak dikurangkan dengan kehadiran urea sahaja (48%) berbanding dengan kehadiran NDS sahaja (18%). Keberkesanan penyingkiran protein yang lebih tinggi (55%) mungkin telah disebabkan oleh kesan sinergi apabila kedua-dua urea dan NDS digunakan di dalam penyahprotein lateks. Nilai keupayaan zeta yang tinggi diperhatikan apabila hanya NDS digunakan, menunjukkan kestabilan koloid yang lebih tinggi. Pengimbas Persekitaran Mikroskopi Elektron (ESEM) menunjukkan bahawa tanpa NDS, penggunaan hanya urea dalam proses penyahprotein menyumbang kepada kesan pengagregatan zarah lateks, kemungkinan disebabkan oleh penyingkiran protein lateks yang membantu dalam kestabilan koloid lateks. Oleh yang demikian, besar kemungkinan fungsi utama urea semasa proses penyahprotein lateks adalah sebagai ejen pembuka protein manakala NDS berfungsi sebagai penstabil lateks tanpa kesan ketara pada penyingkiran protein lateks.

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Section: Results and Discussion Protein Contents And Zeta Potentialsmentioning

confidence: 94%

Section: Results and Discussion Protein Contents And Zeta Potentialsmentioning

confidence: 99%

Zeta Potential and Environmental Scanning Electron Microscopy Analysis in Deproteinisation of Natural Rubber Latex

Abdullah¹

2016

MJAS

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“…This suggests that the Elodea leaves easily absorbed exogenous urea. It is known that urea can be accumulated by the plant roots themselves and assimilate into root cells, but high concentrations of urea cause denaturation of protein molecules (Lima et al 2009;Rossky 2008). Urea is able to interact with both polar and non-polar groups of proteins, leading to the destruction of their tertiary structure.…”

Section: Discussionmentioning

confidence: 99%

Influence of exogenous urea on photosynthetic pigments, 14CO2 uptake, and urease activity in Elodea densa—environmental implications

Maleva

Borisova

Чукина

et al. 2013

Environ Sci Pollut Res

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This paper analyzes the effect of exogenous urea in increased concentration gradient (0, 100, 500 and 1,000 mg L −1 ) on photosynthetic pigments (measured spectrophotometrically), uptake of 14 CO 2 (using radioisotope), and urease activity (by measuring ammonia with Nessler's reagent) in leaves of Elodea densa Planch. We have observed that low concentration of urea (100 mg L −1 ) stimulates the accumulation of photosynthetic pigments and intensifies photosynthesis in E. densa, whereas high concentration (1,000 mg L −1 ) suppresses these processes. Urease activity increased by approximately 2.7 and 8 fold when exogenous urea concentrations were 100 and 500 mg L −1 , respectively. However, exogenous urea in high concentration (1,000 mg L −1 ) decreased urease activity by 1.5 fold compared to the control. The necessity of mitigating urea and other nitrogen-containing compounds (NH 3 from urea) in water bodies has been discussed with emphasis on the potential for phytoremediation of urea using common water weed viz. E. densa.

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Two major proposals concerning the mode of urea action have been put forward. 15,17 The direct mechanism implies the existence of direct van der Waals or hydrogen bonding or other electrostatic interactions between urea and protein groups. 8,9,18 In the indirect mechanism, urea exerts its effect via perturbation of the structure of water and the related modulation of protein-water interactions.…”

mentioning

confidence: 99%

“…15,19,20 The issue of determination of the specific mode of urea action remains controversial, although the direct mechanism appears to be increasingly favored by the researchers. 17,21,22 The quest for understanding the relative importance of urea interactions with polar versus nonpolar groups is yet another recurrent theme in current investigations.…”

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confidence: 99%

Urea interactions with protein groups: A volumetric study

2010

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We determined the partial molar volumes and adiabatic compressibilities of N-acetyl amino acid amides, N-acetyl amino acid methylamides, N-acetyl amino acids, and short oligoglycines as a function of urea concentration. We analyze these data within the framework of a statistical thermodynamic formalism to determine the association constants for the reaction in which urea binds to the glycyl unit and each of the naturally occurring amino acid side chains replacing two waters of hydration. Our determined association constants, k, range from 0.04 to 0.39 M. We derive a general equation that links k with changes in free energy, DeltaGtr, accompanying the transfer of functional groups from water to urea. In this equation, DeltaGtr is the sum of a change in the free energy of cavity formation, DeltaDeltaGC, and the differential free energy of solute-solvent interactions, DeltaDeltaGI, in urea and water. The observed range of affinity coefficients, k, corresponds to the values of DeltaDeltaGI ranging from highly favorable to slightly unfavorable. Taken together, our data support a direct interaction model in which urea denatures a protein by concerted action via favorable interactions with a wide range of protein groups. Our derived equation linking k to DeltaGtr suggests that DeltaDeltaGI and, hence, the net transfer free energy, DeltaGtr, are both strongly influenced by the concentration of a solute used in the experiment. We emphasize the need to exercise caution when two solutes differing in solubility are compared to determine the DeltaGtr contribution of a particular functional group.

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Protein denaturation by urea: Slash and bond

Cited by 136 publications

References 20 publications

Zeta Potential and Environmental Scanning Electron Microscopy Analysis in Deproteinisation of Natural Rubber Latex

Zeta Potential and Environmental Scanning Electron Microscopy Analysis in Deproteinisation of Natural Rubber Latex

Influence of exogenous urea on photosynthetic pigments, 14CO2 uptake, and urease activity in Elodea densa—environmental implications

Urea interactions with protein groups: A volumetric study

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