Beta-lactoglobulin denaturation by dissociation-coupled unfolding

D Galani, Richard KO Apenten

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Many food proteins have multiple subunits. Beta-lactoglobulin (beta-1g) dimer was assessed for its resistance to subunit dissociation and unfolding in 0-8 M urea. Equilibrium denaturation profiles were monitored by ultraviolet difference spectrophotometry. The results were analysed by a new dissociation coupled unfolding (DCU) model. The Gibbs free energy change for denaturing beta-1g (Delta G(DCU)(0)) was 60 (+/- 2.3) kJ mol(-1) at pH 7 and 72 (+/- 1.6) kJ mol(-1) at pH 2.6. By comparison, the dissociation free energy for beta-1g dimer (Delta G(D)) is 26.0 kJ mol(-1) at pH 7 and 22.6 kJ mol(-1) at pH 2.6. Hence, dimerization accounts for 43% (pH 7) and 32% (pH 2.6) of the stability of native beta-1g dimer. Such results indicate a 3-state denaturation process in urea with native beta-1g monomer acting as a stable intermediate during DCU. The issues raised by a study of beta-1g may be relevant to other multisubunit proteins in food systems.
LanguageEnglish
Pages93-100
JournalFood Research International
Volume32
Issue number2
Publication statusPublished - 1999

Fingerprint

Lactoglobulins
beta-lactoglobulin
denaturation
protein sources
Urea
urea
Ultraviolet Spectrophotometry
Gibbs free energy
Food
dimerization
Dimerization
spectroscopy
Proteins
energy

Keywords

  • BOVINE ALPHA-LACTALBUMIN
  • NERVE GROWTH-FACTOR
  • THERMAL-DENATURATION
  • CONFORMATIONAL STABILITY
  • EQUILIBRIUM DENATURATION
  • ESCHERICHIA-COLI
  • GLOBULAR-PROTEINS
  • SELF-ASSOCIATION
  • SPECTROSCOPY
  • RESOLUTION

Cite this

Galani, D., & Apenten, R. KO. (1999). Beta-lactoglobulin denaturation by dissociation-coupled unfolding. 32(2), 93-100.
Galani, D ; Apenten, Richard KO. / Beta-lactoglobulin denaturation by dissociation-coupled unfolding. 1999 ; Vol. 32, No. 2. pp. 93-100.
@article{832a56cb79c04c569fb25406851cb739,
title = "Beta-lactoglobulin denaturation by dissociation-coupled unfolding",
abstract = "Many food proteins have multiple subunits. Beta-lactoglobulin (beta-1g) dimer was assessed for its resistance to subunit dissociation and unfolding in 0-8 M urea. Equilibrium denaturation profiles were monitored by ultraviolet difference spectrophotometry. The results were analysed by a new dissociation coupled unfolding (DCU) model. The Gibbs free energy change for denaturing beta-1g (Delta G(DCU)(0)) was 60 (+/- 2.3) kJ mol(-1) at pH 7 and 72 (+/- 1.6) kJ mol(-1) at pH 2.6. By comparison, the dissociation free energy for beta-1g dimer (Delta G(D)) is 26.0 kJ mol(-1) at pH 7 and 22.6 kJ mol(-1) at pH 2.6. Hence, dimerization accounts for 43{\%} (pH 7) and 32{\%} (pH 2.6) of the stability of native beta-1g dimer. Such results indicate a 3-state denaturation process in urea with native beta-1g monomer acting as a stable intermediate during DCU. The issues raised by a study of beta-1g may be relevant to other multisubunit proteins in food systems.",
keywords = "BOVINE ALPHA-LACTALBUMIN, NERVE GROWTH-FACTOR, THERMAL-DENATURATION, CONFORMATIONAL STABILITY, EQUILIBRIUM DENATURATION, ESCHERICHIA-COLI, GLOBULAR-PROTEINS, SELF-ASSOCIATION, SPECTROSCOPY, RESOLUTION",
author = "D Galani and Apenten, {Richard KO}",
note = "Reference text: 1. ALBERTY RA PHYSICAL CHEM : 150 1992 2. ALEXANDER SS COMPARISON OF DENATURATION OF BOVINE BETA-LACTOGLOBULINS-A AND B AND GOAT BETA-LACTOGLOBULIN BIOCHEMISTRY 10 : 2738 1971 3. APENTEN RKO The effect of protein unfolding stability on their rates of irreversible denaturation FOOD HYDROCOLLOIDS 12 : 1 1998 4. APENTEN RKO Protein stability function relations: beta-lactoglobulin-A sulphydryl group reactivity and its relationship to protein unfolding stability INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES 23 : 19 1998 5. APENTEN RKO THERMODYNAMIC PARAMETERS FOR 3-STATE THERMAL-DENATURATION OF HUMAN AND BOVINE ALPHA-LACTALBUMIN THERMOCHIMICA ACTA 262 : 1 1995 6. ARMSTRONG J ON FRACTIONATION OF BETA-LACTOGLOBULIN AND ALPHA-LACTALBUMIN BIOCHIMICA ET BIOPHYSICA ACTA 147 : 60 1967 7. ARMSTRONG JM ON COLUMN CHROMATOGRAPHY OF BOVINE WHEY PROTEINS BIOCHIMICA ET BIOPHYSICA ACTA 214 : 419 1970 8. AYMARD P The effect of temperature and ionic strength on the dimerisation of beta-lactoglobulin INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES 19 : 213 1996 9. BOWIE JU EQUILIBRIUM DISSOCIATION AND UNFOLDING OF THE ARC REPRESSOR DIMER BIOCHEMISTRY 28 : 7139 1989 10. BROWNLOW S Bovine beta-lactoglobulin at 1.8 angstrom resolution - Still an enigmatic lipocalin STRUCTURE 5 : 481 1997 11. CHENG XD ENERGETICS OF INTERSUBUNIT AND INTRASUBUNIT INTERACTIONS OF ESCHERICHIA-COLI ADENOSINE CYCLIC 3',5'-PHOSPHATE RECEPTOR PROTEIN BIOCHEMISTRY 32 : 8130 1993 12. CREAMER LK EFFECT OF SODIUM DODECYL-SULFATE AND PALMITIC ACID ON THE EQUILIBRIUM UNFOLDING OF BOVINE BETA-LACTOGLOBULIN BIOCHEMISTRY 34 : 7170 1995 13. CUPO JF CONFORMATIONAL STABILITY OF MIXED DISULFIDE DERIVATIVES OF BETA-LACTOGLOBULIN-B BIOCHEMISTRY 22 : 2654 1983 14. ELOFSSON UM Adsorption of beta-lactoglobulin A and B in relation to self-association: Effect of concentration and pH LANGMUIR 13 : 1695 1997 15. GRANT SK USE OF PROTEIN UNFOLDING STUDIES TO DETERMINE THE CONFORMATIONAL AND DIMERIC STABILITIES OF HIV-1 AND SIV PROTEASES BIOCHEMISTRY 31 : 9491 1992 16. HEROLD M REVERSIBLE DISSOCIATION AND UNFOLDING OF ASPARTATE-AMINOTRANSFERASE FROM ESCHERICHIA-COLI - CHARACTERIZATION OF A MONOMERIC INTERMEDIATE BIOCHEMISTRY 29 : 1907 1990 17. IWABUCHI S THERMAL-DENATURATION OF BETA-CONGLYCININ - KINETIC RESOLUTION OF REACTION-MECHANISM JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 39 : 27 1991 18. JAENICKE R PROTEIN STRUCTURE PR : 117 1989 19. JOSS LA beta-lactoglobulin B: A proposed standard for the study of reversible self-association reactions in the analytical ultracentrifuge? ANALYTICAL BIOCHEMISTRY 236 : 20 1996 20. KELLA NKD ENHANCED THERMODYNAMIC STABILITY OF BETA-LACTOGLOBULIN AT LOW PH - A POSSIBLE MECHANISM BIOCHEMICAL JOURNAL 255 : 113 1988 21. KELLA NKD STRUCTURAL STABILITY OF BETA-LACTOGLOBULIN IN THE PRESENCE OF KOSMOTROPIC SALTS - A KINETIC AND THERMODYNAMIC STUDY INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 32 : 396 1988 22. KELLY MJ THERMODYNAMIC ANALYSIS OF MONOMER-DIMER ASSOCIATION OF BETA-LACTOGLOBULIN-A AT ISOELECTRIC POINT BIOCHEMISTRY 10 : 2639 1971 23. LAPANJE S CALORIMETRIC AND CIRCULAR DICHROIC STUDIES OF THE THERMAL-DENATURATION OF BETA-LACTOGLOBULIN BIOPHYSICAL CHEMISTRY 34 : 155 1989 24. MANN CJ TRYPTOPHAN REPLACEMENTS IN THE TRP APOREPRESSOR FROM ESCHERICHIA-COLI - PROBING THE EQUILIBRIUM AND KINETIC FOLDING MODELS PROTEIN SCIENCE 2 : 1853 1993 25. MATSUURA JE HEAT-INDUCED GEL FORMATION OF BETA-LACTOGLOBULIN - A STUDY ON THE SECONDARY AND TERTIARY STRUCTURE AS FOLLOWED BY CIRCULAR-DICHROISM SPECTROSCOPY JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 42 : 1650 1994 26. MOLINARI H Partially folded structure of monomeric bovine beta-lactoglobulin FEBS LETTERS 381 : 237 1996 27. NEET KE CONFORMATIONAL STABILITY OF DIMERIC PROTEINS - QUANTITATIVE STUDIES BY EQUILIBRIUM DENATURATION PROTEIN SCIENCE 3 : 2167 1994 28. OWUSU RK THERMODYNAMIC ANALYSIS OF THE EFFECT OF CALCIUM ON BOVINE ALPHA-LACTALBUMIN CONFORMATIONAL STABILITY FOOD CHEMISTRY 44 : 189 1992 29. OWUSU RK THE EFFECT OF CALCIUM ON BOVINE ALPHA-LACTALBUMIN CONFORMATIONAL TRANSITIONS BY ULTRAVIOLET DIFFERENCE AND FLUORESCENCE SPECTROPHOTOMETRY FOOD CHEMISTRY 43 : 41 1992 30. PACE CN METHOD ENZYMOL 131 : 266 1986",
year = "1999",
language = "English",
volume = "32",
pages = "93--100",
number = "2",

}

Galani, D & Apenten, RKO 1999, 'Beta-lactoglobulin denaturation by dissociation-coupled unfolding', vol. 32, no. 2, pp. 93-100.

Beta-lactoglobulin denaturation by dissociation-coupled unfolding. / Galani, D; Apenten, Richard KO.

Vol. 32, No. 2, 1999, p. 93-100.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Beta-lactoglobulin denaturation by dissociation-coupled unfolding

AU - Galani, D

AU - Apenten, Richard KO

N1 - Reference text: 1. ALBERTY RA PHYSICAL CHEM : 150 1992 2. ALEXANDER SS COMPARISON OF DENATURATION OF BOVINE BETA-LACTOGLOBULINS-A AND B AND GOAT BETA-LACTOGLOBULIN BIOCHEMISTRY 10 : 2738 1971 3. APENTEN RKO The effect of protein unfolding stability on their rates of irreversible denaturation FOOD HYDROCOLLOIDS 12 : 1 1998 4. APENTEN RKO Protein stability function relations: beta-lactoglobulin-A sulphydryl group reactivity and its relationship to protein unfolding stability INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES 23 : 19 1998 5. APENTEN RKO THERMODYNAMIC PARAMETERS FOR 3-STATE THERMAL-DENATURATION OF HUMAN AND BOVINE ALPHA-LACTALBUMIN THERMOCHIMICA ACTA 262 : 1 1995 6. ARMSTRONG J ON FRACTIONATION OF BETA-LACTOGLOBULIN AND ALPHA-LACTALBUMIN BIOCHIMICA ET BIOPHYSICA ACTA 147 : 60 1967 7. ARMSTRONG JM ON COLUMN CHROMATOGRAPHY OF BOVINE WHEY PROTEINS BIOCHIMICA ET BIOPHYSICA ACTA 214 : 419 1970 8. AYMARD P The effect of temperature and ionic strength on the dimerisation of beta-lactoglobulin INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES 19 : 213 1996 9. BOWIE JU EQUILIBRIUM DISSOCIATION AND UNFOLDING OF THE ARC REPRESSOR DIMER BIOCHEMISTRY 28 : 7139 1989 10. BROWNLOW S Bovine beta-lactoglobulin at 1.8 angstrom resolution - Still an enigmatic lipocalin STRUCTURE 5 : 481 1997 11. CHENG XD ENERGETICS OF INTERSUBUNIT AND INTRASUBUNIT INTERACTIONS OF ESCHERICHIA-COLI ADENOSINE CYCLIC 3',5'-PHOSPHATE RECEPTOR PROTEIN BIOCHEMISTRY 32 : 8130 1993 12. CREAMER LK EFFECT OF SODIUM DODECYL-SULFATE AND PALMITIC ACID ON THE EQUILIBRIUM UNFOLDING OF BOVINE BETA-LACTOGLOBULIN BIOCHEMISTRY 34 : 7170 1995 13. CUPO JF CONFORMATIONAL STABILITY OF MIXED DISULFIDE DERIVATIVES OF BETA-LACTOGLOBULIN-B BIOCHEMISTRY 22 : 2654 1983 14. ELOFSSON UM Adsorption of beta-lactoglobulin A and B in relation to self-association: Effect of concentration and pH LANGMUIR 13 : 1695 1997 15. GRANT SK USE OF PROTEIN UNFOLDING STUDIES TO DETERMINE THE CONFORMATIONAL AND DIMERIC STABILITIES OF HIV-1 AND SIV PROTEASES BIOCHEMISTRY 31 : 9491 1992 16. HEROLD M REVERSIBLE DISSOCIATION AND UNFOLDING OF ASPARTATE-AMINOTRANSFERASE FROM ESCHERICHIA-COLI - CHARACTERIZATION OF A MONOMERIC INTERMEDIATE BIOCHEMISTRY 29 : 1907 1990 17. IWABUCHI S THERMAL-DENATURATION OF BETA-CONGLYCININ - KINETIC RESOLUTION OF REACTION-MECHANISM JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 39 : 27 1991 18. JAENICKE R PROTEIN STRUCTURE PR : 117 1989 19. JOSS LA beta-lactoglobulin B: A proposed standard for the study of reversible self-association reactions in the analytical ultracentrifuge? ANALYTICAL BIOCHEMISTRY 236 : 20 1996 20. KELLA NKD ENHANCED THERMODYNAMIC STABILITY OF BETA-LACTOGLOBULIN AT LOW PH - A POSSIBLE MECHANISM BIOCHEMICAL JOURNAL 255 : 113 1988 21. KELLA NKD STRUCTURAL STABILITY OF BETA-LACTOGLOBULIN IN THE PRESENCE OF KOSMOTROPIC SALTS - A KINETIC AND THERMODYNAMIC STUDY INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 32 : 396 1988 22. KELLY MJ THERMODYNAMIC ANALYSIS OF MONOMER-DIMER ASSOCIATION OF BETA-LACTOGLOBULIN-A AT ISOELECTRIC POINT BIOCHEMISTRY 10 : 2639 1971 23. LAPANJE S CALORIMETRIC AND CIRCULAR DICHROIC STUDIES OF THE THERMAL-DENATURATION OF BETA-LACTOGLOBULIN BIOPHYSICAL CHEMISTRY 34 : 155 1989 24. MANN CJ TRYPTOPHAN REPLACEMENTS IN THE TRP APOREPRESSOR FROM ESCHERICHIA-COLI - PROBING THE EQUILIBRIUM AND KINETIC FOLDING MODELS PROTEIN SCIENCE 2 : 1853 1993 25. MATSUURA JE HEAT-INDUCED GEL FORMATION OF BETA-LACTOGLOBULIN - A STUDY ON THE SECONDARY AND TERTIARY STRUCTURE AS FOLLOWED BY CIRCULAR-DICHROISM SPECTROSCOPY JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 42 : 1650 1994 26. MOLINARI H Partially folded structure of monomeric bovine beta-lactoglobulin FEBS LETTERS 381 : 237 1996 27. NEET KE CONFORMATIONAL STABILITY OF DIMERIC PROTEINS - QUANTITATIVE STUDIES BY EQUILIBRIUM DENATURATION PROTEIN SCIENCE 3 : 2167 1994 28. OWUSU RK THERMODYNAMIC ANALYSIS OF THE EFFECT OF CALCIUM ON BOVINE ALPHA-LACTALBUMIN CONFORMATIONAL STABILITY FOOD CHEMISTRY 44 : 189 1992 29. OWUSU RK THE EFFECT OF CALCIUM ON BOVINE ALPHA-LACTALBUMIN CONFORMATIONAL TRANSITIONS BY ULTRAVIOLET DIFFERENCE AND FLUORESCENCE SPECTROPHOTOMETRY FOOD CHEMISTRY 43 : 41 1992 30. PACE CN METHOD ENZYMOL 131 : 266 1986

PY - 1999

Y1 - 1999

N2 - Many food proteins have multiple subunits. Beta-lactoglobulin (beta-1g) dimer was assessed for its resistance to subunit dissociation and unfolding in 0-8 M urea. Equilibrium denaturation profiles were monitored by ultraviolet difference spectrophotometry. The results were analysed by a new dissociation coupled unfolding (DCU) model. The Gibbs free energy change for denaturing beta-1g (Delta G(DCU)(0)) was 60 (+/- 2.3) kJ mol(-1) at pH 7 and 72 (+/- 1.6) kJ mol(-1) at pH 2.6. By comparison, the dissociation free energy for beta-1g dimer (Delta G(D)) is 26.0 kJ mol(-1) at pH 7 and 22.6 kJ mol(-1) at pH 2.6. Hence, dimerization accounts for 43% (pH 7) and 32% (pH 2.6) of the stability of native beta-1g dimer. Such results indicate a 3-state denaturation process in urea with native beta-1g monomer acting as a stable intermediate during DCU. The issues raised by a study of beta-1g may be relevant to other multisubunit proteins in food systems.

AB - Many food proteins have multiple subunits. Beta-lactoglobulin (beta-1g) dimer was assessed for its resistance to subunit dissociation and unfolding in 0-8 M urea. Equilibrium denaturation profiles were monitored by ultraviolet difference spectrophotometry. The results were analysed by a new dissociation coupled unfolding (DCU) model. The Gibbs free energy change for denaturing beta-1g (Delta G(DCU)(0)) was 60 (+/- 2.3) kJ mol(-1) at pH 7 and 72 (+/- 1.6) kJ mol(-1) at pH 2.6. By comparison, the dissociation free energy for beta-1g dimer (Delta G(D)) is 26.0 kJ mol(-1) at pH 7 and 22.6 kJ mol(-1) at pH 2.6. Hence, dimerization accounts for 43% (pH 7) and 32% (pH 2.6) of the stability of native beta-1g dimer. Such results indicate a 3-state denaturation process in urea with native beta-1g monomer acting as a stable intermediate during DCU. The issues raised by a study of beta-1g may be relevant to other multisubunit proteins in food systems.

KW - BOVINE ALPHA-LACTALBUMIN

KW - NERVE GROWTH-FACTOR

KW - THERMAL-DENATURATION

KW - CONFORMATIONAL STABILITY

KW - EQUILIBRIUM DENATURATION

KW - ESCHERICHIA-COLI

KW - GLOBULAR-PROTEINS

KW - SELF-ASSOCIATION

KW - SPECTROSCOPY

KW - RESOLUTION

M3 - Article

VL - 32

SP - 93

EP - 100

IS - 2

ER -