Thermal stability of proteins in the presence of poly(ethylene glycols)

Lucy L Y Lee, James Lee

Research output: Contribution to journalArticle

183 Citations (Scopus)

Abstract

Thermal unfolding of ribonuclease, lysozyme, chymotrypsinogen, and β-lactoglobulin was studied in the absence or presence of poly(ethylene glycols). The unfolding curves were fitted to a two-state model by a nonlinear least-squares program to obtain values of ΔH, ΔS, and the melting temperature Tm. A decrease in thermal transition temperature was observed in the presence of poly(ethylene glycol) for all of the protein systems studied. The magnitude of such a decrease depends on the particular protein and the molecular size of poly(ethylene glycol) employed. A linear relation can be established between the magnitude of the decrease in transition temperature and the average hydrophobicity of these proteins; namely, the largest observable decrease is associated with the protein of the highest hydrophobicity. Further analysis of the thermal unfolding data reveals that poly(ethylene glycols) significantly effect the relation between ΔH° of unfolding and temperature for all the proteins studied. For β-lactoglobulin, a plot of ΔH versus Tm indicates a change in slope from a negative to a positive value, thus implying a change in ΔCp in thermal unfolding caused by the presence of poly(ethylene glycols). Results from solvent-protein interaction studies indicate that at high temperature poly(ethylene glycol) 1000 preferentially interacts with the denatured state of protein but is excluded from the native state at low temperature. These observations are consistent with the fact that poly(ethylene glycols) are hydrophobic in nature and will interact favorably with the hydrophobic side chains exposed upon unfolding; thus, it leads to a lowering of thermal transition temperature.

Original languageEnglish (US)
Pages (from-to)7813-7819
Number of pages7
JournalBiochemistry
Volume26
Issue number24
StatePublished - 1987
Externally publishedYes

Fingerprint

Ethylene Glycols
Protein Stability
Polyethylene glycols
Thermodynamic stability
Hot Temperature
Ethylene Glycol
Transition Temperature
Proteins
Lactoglobulins
Temperature
Hydrophobicity
Hydrophobic and Hydrophilic Interactions
Chymotrypsinogen
Ribonucleases
Muramidase
Least-Squares Analysis
Freezing
Melting point

ASJC Scopus subject areas

  • Biochemistry

Cite this

Lee, L. L. Y., & Lee, J. (1987). Thermal stability of proteins in the presence of poly(ethylene glycols). Biochemistry, 26(24), 7813-7819.

Thermal stability of proteins in the presence of poly(ethylene glycols). / Lee, Lucy L Y; Lee, James.

In: Biochemistry, Vol. 26, No. 24, 1987, p. 7813-7819.

Research output: Contribution to journalArticle

Lee, LLY & Lee, J 1987, 'Thermal stability of proteins in the presence of poly(ethylene glycols)', Biochemistry, vol. 26, no. 24, pp. 7813-7819.
Lee, Lucy L Y ; Lee, James. / Thermal stability of proteins in the presence of poly(ethylene glycols). In: Biochemistry. 1987 ; Vol. 26, No. 24. pp. 7813-7819.
@article{4c1462d9a397468daa1417c2e9cda6b4,
title = "Thermal stability of proteins in the presence of poly(ethylene glycols)",
abstract = "Thermal unfolding of ribonuclease, lysozyme, chymotrypsinogen, and β-lactoglobulin was studied in the absence or presence of poly(ethylene glycols). The unfolding curves were fitted to a two-state model by a nonlinear least-squares program to obtain values of ΔH, ΔS, and the melting temperature Tm. A decrease in thermal transition temperature was observed in the presence of poly(ethylene glycol) for all of the protein systems studied. The magnitude of such a decrease depends on the particular protein and the molecular size of poly(ethylene glycol) employed. A linear relation can be established between the magnitude of the decrease in transition temperature and the average hydrophobicity of these proteins; namely, the largest observable decrease is associated with the protein of the highest hydrophobicity. Further analysis of the thermal unfolding data reveals that poly(ethylene glycols) significantly effect the relation between ΔH° of unfolding and temperature for all the proteins studied. For β-lactoglobulin, a plot of ΔH versus Tm indicates a change in slope from a negative to a positive value, thus implying a change in ΔCp in thermal unfolding caused by the presence of poly(ethylene glycols). Results from solvent-protein interaction studies indicate that at high temperature poly(ethylene glycol) 1000 preferentially interacts with the denatured state of protein but is excluded from the native state at low temperature. These observations are consistent with the fact that poly(ethylene glycols) are hydrophobic in nature and will interact favorably with the hydrophobic side chains exposed upon unfolding; thus, it leads to a lowering of thermal transition temperature.",
author = "Lee, {Lucy L Y} and James Lee",
year = "1987",
language = "English (US)",
volume = "26",
pages = "7813--7819",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",
number = "24",

}

TY - JOUR

T1 - Thermal stability of proteins in the presence of poly(ethylene glycols)

AU - Lee, Lucy L Y

AU - Lee, James

PY - 1987

Y1 - 1987

N2 - Thermal unfolding of ribonuclease, lysozyme, chymotrypsinogen, and β-lactoglobulin was studied in the absence or presence of poly(ethylene glycols). The unfolding curves were fitted to a two-state model by a nonlinear least-squares program to obtain values of ΔH, ΔS, and the melting temperature Tm. A decrease in thermal transition temperature was observed in the presence of poly(ethylene glycol) for all of the protein systems studied. The magnitude of such a decrease depends on the particular protein and the molecular size of poly(ethylene glycol) employed. A linear relation can be established between the magnitude of the decrease in transition temperature and the average hydrophobicity of these proteins; namely, the largest observable decrease is associated with the protein of the highest hydrophobicity. Further analysis of the thermal unfolding data reveals that poly(ethylene glycols) significantly effect the relation between ΔH° of unfolding and temperature for all the proteins studied. For β-lactoglobulin, a plot of ΔH versus Tm indicates a change in slope from a negative to a positive value, thus implying a change in ΔCp in thermal unfolding caused by the presence of poly(ethylene glycols). Results from solvent-protein interaction studies indicate that at high temperature poly(ethylene glycol) 1000 preferentially interacts with the denatured state of protein but is excluded from the native state at low temperature. These observations are consistent with the fact that poly(ethylene glycols) are hydrophobic in nature and will interact favorably with the hydrophobic side chains exposed upon unfolding; thus, it leads to a lowering of thermal transition temperature.

AB - Thermal unfolding of ribonuclease, lysozyme, chymotrypsinogen, and β-lactoglobulin was studied in the absence or presence of poly(ethylene glycols). The unfolding curves were fitted to a two-state model by a nonlinear least-squares program to obtain values of ΔH, ΔS, and the melting temperature Tm. A decrease in thermal transition temperature was observed in the presence of poly(ethylene glycol) for all of the protein systems studied. The magnitude of such a decrease depends on the particular protein and the molecular size of poly(ethylene glycol) employed. A linear relation can be established between the magnitude of the decrease in transition temperature and the average hydrophobicity of these proteins; namely, the largest observable decrease is associated with the protein of the highest hydrophobicity. Further analysis of the thermal unfolding data reveals that poly(ethylene glycols) significantly effect the relation between ΔH° of unfolding and temperature for all the proteins studied. For β-lactoglobulin, a plot of ΔH versus Tm indicates a change in slope from a negative to a positive value, thus implying a change in ΔCp in thermal unfolding caused by the presence of poly(ethylene glycols). Results from solvent-protein interaction studies indicate that at high temperature poly(ethylene glycol) 1000 preferentially interacts with the denatured state of protein but is excluded from the native state at low temperature. These observations are consistent with the fact that poly(ethylene glycols) are hydrophobic in nature and will interact favorably with the hydrophobic side chains exposed upon unfolding; thus, it leads to a lowering of thermal transition temperature.

UR - http://www.scopus.com/inward/record.url?scp=0023505188&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023505188&partnerID=8YFLogxK

M3 - Article

C2 - 3427106

AN - SCOPUS:0023505188

VL - 26

SP - 7813

EP - 7819

JO - Biochemistry

JF - Biochemistry

SN - 0006-2960

IS - 24

ER -