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

Richard Owusu

doi:10.1016/0308-8146(92)90186-6

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

Richard Owusu

Faculty Of Life & Health Sciences

Research output: Contribution to journal › Article

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.

Original language	English
Pages (from-to)	189-194
Journal	Food Chemistry
Volume	44
Issue number	3
DOIs	https://doi.org/10.1016/0308-8146(92)90186-6
Publication status	Published - 1992

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@article{525b559be6a74e9b99e91c2bb9781a23,

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.",

author = "Richard Owusu",

year = "1992",

doi = "10.1016/0308-8146(92)90186-6",

language = "English",

volume = "44",

pages = "189--194",

journal = "Food Chemistry",

issn = "0308-8146",

publisher = "Elsevier",

number = "3",

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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.

U2 - 10.1016/0308-8146(92)90186-6

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

M3 - Article

VL - 44

SP - 189

EP - 194

JO - Food Chemistry

JF - Food Chemistry

SN - 0308-8146

IS - 3

ER -