Biomaterial Database

[A comparative thermodynamic study of heat and cold denaturation of beta-lactoglobulin]. 1992

Iu V Griko, and S Iu Ben'iaminov, and P L Privalov

The changes in structure and thermodynamic parameters of beta-lactoglobulin upon heat and cold denaturation have been studied using both scanning microcalorimetry and circular dichroism spectroscopy methods. It has been shown that in contrast to the heat denaturation process, the cold denaturation of beta-lactoglobulin is accompanied by an opposite heat effect. In all cases, the calorimetrically measured enthalpy of beta-lactoglobulin cold denaturation is higher than it was expected from the two-state model of denaturation transition. It has been concluded that beta-lactoglobulin cold denaturation cannot be represented by a transition between two microscopic states--native and denatured. The latter, is due to the additional process that occurs together with the disruption of the beta-lactoglobulin tertiary structure and is accompanied by increasing heat capacity. Taking into account the heat capacity contribution of this process upon calculation of the enthalpy makes it closer to the enthalpy value calculated for the two-state model of denaturation transition.

UI	MeSH Term	Description	Entries
D007782	Lactoglobulins	Globulins of milk obtained from the WHEY.	Lactoglobulin,beta-Lactoglobulin,beta-Lactoglobulin A,beta-Lactoglobulin B,beta-Lactoglobulin C,beta-Lactoglobulin E,beta-Lactoglobulin F,beta-Lactoglobulin G,beta-Lactoglobulin I,beta Lactoglobulin,beta Lactoglobulin A,beta Lactoglobulin B,beta Lactoglobulin C,beta Lactoglobulin E,beta Lactoglobulin F,beta Lactoglobulin G,beta Lactoglobulin I
D011489	Protein Denaturation	Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.	Denaturation, Protein,Denaturations, Protein,Protein Denaturations
D002152	Calorimetry, Differential Scanning	Differential thermal analysis in which the sample compartment of the apparatus is a differential calorimeter, allowing an exact measure of the heat of transition independent of the specific heat, thermal conductivity, and other variables of the sample.	Differential Thermal Analysis, Calorimetric,Calorimetric Differential Thermal Analysis,Differential Scanning Calorimetry,Scanning Calorimetry, Differential
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D013816	Thermodynamics	A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)	Thermodynamic