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REVISED CONFORMATIONAL STABILITY PARAMETERS FOR BETA‐LACTOGLOBULIN ISOTHERMAL DENATURATION BY UREA
Author(s) -
OWUSUAPENTEN RICHARD K.
Publication year - 2002
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.2002.tb00851.x
Subject(s) - chemistry , denaturation (fissile materials) , dimer , gibbs free energy , urea , equilibrium unfolding , guanidine , dissociation (chemistry) , native state , isothermal process , crystallography , protein folding , monomer , thermodynamics , circular dichroism , biochemistry , organic chemistry , nuclear chemistry , polymer , physics
Isothermal unfolding studies for beta‐lactoglobulin (β‐Lg) usually apply a denaturation model suitable for a single submit protein. A method is described for correcting such results in retrospect. This leads to accurate estimates for the Gibbsfree energy of stabilization of native β‐Lg aimer. The denaturation of β‐Lg aimer is described by a dissociation coupled unfolding (DCU) process; Dimer → monomer → unfolded state. The Gibbs free energy change for DCU (ΔG° DCU ) was 80 kJ mol −1 at pH 7 and 97 kJ mol −1 for β‐Lg at pH 2.6. With the addition of a range of salts (pH 6.85) then ΔG° DCU increased to 105 kJ mol −1 . The literature is replete with denaturation studies employing β‐Lg as the principal protein. In many instances, it would be prudent to reevaluate stability data for β‐Lg in line with techniques outlined here.