Publisher Summary This chapter explores that the changes that take place in the protein molecules during denaturation constitute one of the most interesting and complex classes of reactions that can be found either in nature or in the laboratory These reactions are important because of the information they can provide about the more intimate details of protein structure and function They are also significant because they challenge the chemist with a difficult area for the application of chemical principles The chapter reviews that the denaturation is a process in which the spatial arrangement of the polypeptide chains within the molecule is changed from that typical of the native protein to a more disordered arrangement The chapter also discusses the classification of protein structures: primary, secondary, and tertiary structures The primary structure is that expressed by the structural chemical formula and depends entirely on the chemical valence bonds that the classical organic chemist would write down for the protein molecule The secondary structure is the configuration of the polypeptide chain that results from the satisfaction of the hydrogen bonding potential between the peptide N-H and C=O groups The tertiary structure is the pattern according to which the secondary structures are packed together within the native protein molecule The term “denaturation” as used in this chapter is indented to include changes in both the secondary and tertiary structures

Some factors in the interpretation of protein denaturation.

Solubilization of membranes by detergents

Nomenclature of the Proteins of Cows’ Milk—Sixth Revision

The stabilization of proteins by sucrose.

Publisher Summary This chapter describes many of the techniques employed to study water–macromolecules interactions, their general usefulness, points out areas of mutual support and contradiction. The chapter also presents hydration of other macromolecules and the hydration of small molecules. Four broadly based approaches to operational definitions of hydration include—(1) preferential hydration, (2) hydrodynamic hydration, (3) structural hydration, and (4) low temperature hydration. The use of high resolution X-ray and neutron diffraction data on protein crystals provides an independent approach for estimation of hydration. The chapter presents several proposals for predicting protein hydration based on the amino acid composition of the protein; however, the two main questions concerned include—whether ionic groups are more hydrated than other polar groups, and whether the amide and peptide functions are hydrated or not. Low pH, and to a much smaller degree, high pH should dehydrate proteins. Intermolecular association via ionic mechanisms should be strongly dehydrating; whereas hydrophobic interactions should not have much effect on hydration levels. Although, there is a presumption that both the enthalpy and the entropy are negative for the process of adding water molecules to isolated proteins, which are maintained in their native conformations, but there is no unequivocal evidence for this.

Hydration of Proteins and Polypeptides

Apparent Specific Volume of α-Casein and β-Casein and the Relationship of Specific Volume to Amino Acid Composition

Separation of γ-Casein2

Effect of pH on the Denaturation of β-Lactoglobulin and its Dodecyl Sulfate Derivative

Acid—Base Titration, Viscosity and Density of α-, β- and γ-Casein

Phosphopeptides Obtained by Partial Acid Hydrolysis of α-Casein2

N. J. Hipp

Papers

Apparent Specific Volume of α-Casein and β-Casein and the Relationship of Specific Volume to Amino Acid Composition

Separation of γ-Casein2

Effect of pH on the Denaturation of β-Lactoglobulin and its Dodecyl Sulfate Derivative

Acid—Base Titration, Viscosity and Density of α-, β- and γ-Casein

Phosphopeptides Obtained by Partial Acid Hydrolysis of α-Casein2