Thermodynamic analysis of the effect of calcium on bovine alpha-lactalbumin conformational stability

Richard Owusu

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

ΔG° Values for bovine alpha-lactalbumin (BAL) unfolding in a range of solvents, including simulated milk ultrafiltrate buffer, were determined. The denaturant used was guanidine hydrochloride. In Ca2+-free solvents fluorescence and ultraviolet (UV) difference absorbance unfolding profiles were non-superimposable leading to ΔG° estimates of 15–17 kJ mol−1 and 21–28 kJ mol−1, respectively. Therefore, the unfolding of BAL was consistent with a three-state reaction. The low and high ΔG° estimates may correspond to the loss of BAL 3° and 2° structure, respectively.The presence of excess Ca2+, two BAL unfolding transitions (I and II) were observed with both spectrophotometric techniques. Transition (II) was associated with a ΔG° value of 52 kJ mol− and is probably identical to a two-state BAL unfolding reaction described previously. Transition (I) appears to signify a novel feature of BAL structure.
LanguageEnglish
Pages189-194
JournalFood Chemistry
Volume44
Issue number3
DOIs
Publication statusPublished - 1992

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Lactalbumin
lactalbumin
Thermodynamics
thermodynamics
Calcium
calcium
cattle
guanidines
Guanidine
absorbance
Buffers
Milk
buffers
Fluorescence
fluorescence
milk

Cite this

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title = "Thermodynamic analysis of the effect of calcium on bovine alpha-lactalbumin conformational stability",
abstract = "ΔG° Values for bovine alpha-lactalbumin (BAL) unfolding in a range of solvents, including simulated milk ultrafiltrate buffer, were determined. The denaturant used was guanidine hydrochloride. In Ca2+-free solvents fluorescence and ultraviolet (UV) difference absorbance unfolding profiles were non-superimposable leading to ΔG° estimates of 15–17 kJ mol−1 and 21–28 kJ mol−1, respectively. Therefore, the unfolding of BAL was consistent with a three-state reaction. The low and high ΔG° estimates may correspond to the loss of BAL 3° and 2° structure, respectively.The presence of excess Ca2+, two BAL unfolding transitions (I and II) were observed with both spectrophotometric techniques. Transition (II) was associated with a ΔG° value of 52 kJ mol− and is probably identical to a two-state BAL unfolding reaction described previously. Transition (I) appears to signify a novel feature of BAL structure.",
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Thermodynamic analysis of the effect of calcium on bovine alpha-lactalbumin conformational stability. / Owusu, Richard.

In: Food Chemistry, Vol. 44, No. 3, 1992, p. 189-194.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Thermodynamic analysis of the effect of calcium on bovine alpha-lactalbumin conformational stability

AU - Owusu, Richard

PY - 1992

Y1 - 1992

N2 - ΔG° Values for bovine alpha-lactalbumin (BAL) unfolding in a range of solvents, including simulated milk ultrafiltrate buffer, were determined. The denaturant used was guanidine hydrochloride. In Ca2+-free solvents fluorescence and ultraviolet (UV) difference absorbance unfolding profiles were non-superimposable leading to ΔG° estimates of 15–17 kJ mol−1 and 21–28 kJ mol−1, respectively. Therefore, the unfolding of BAL was consistent with a three-state reaction. The low and high ΔG° estimates may correspond to the loss of BAL 3° and 2° structure, respectively.The presence of excess Ca2+, two BAL unfolding transitions (I and II) were observed with both spectrophotometric techniques. Transition (II) was associated with a ΔG° value of 52 kJ mol− and is probably identical to a two-state BAL unfolding reaction described previously. Transition (I) appears to signify a novel feature of BAL structure.

AB - ΔG° Values for bovine alpha-lactalbumin (BAL) unfolding in a range of solvents, including simulated milk ultrafiltrate buffer, were determined. The denaturant used was guanidine hydrochloride. In Ca2+-free solvents fluorescence and ultraviolet (UV) difference absorbance unfolding profiles were non-superimposable leading to ΔG° estimates of 15–17 kJ mol−1 and 21–28 kJ mol−1, respectively. Therefore, the unfolding of BAL was consistent with a three-state reaction. The low and high ΔG° estimates may correspond to the loss of BAL 3° and 2° structure, respectively.The presence of excess Ca2+, two BAL unfolding transitions (I and II) were observed with both spectrophotometric techniques. Transition (II) was associated with a ΔG° value of 52 kJ mol− and is probably identical to a two-state BAL unfolding reaction described previously. Transition (I) appears to signify a novel feature of BAL structure.

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DO - 10.1016/0308-8146(92)90186-6

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