The molten globule state as a clue for understanding the folding and cooperativity of globular-protein structure.

Recombinant DNA technology has now made it possible to produce proteins for pharmaceutical applications Consequently, proteins produced via biotechnology now comprise a significant portion of the drugs currently under development Isolation, purification, formulation, and delivery of proteins represent significant challenges to pharmaceutical scientists, as proteins possess unique chemical and physical properties These properties pose difficult stability problems A summary of both chemical and physical decomposition pathways for proteins is given Chemical instability can include proteolysis, deamidation, oxidation, racemization, and β-elimination Physical instability refers to processes such as aggregation, precipitation, denaturation, and adsorption to surfaces Current methodology to stabilize proteins is presented, including additives, excipients, chemical modification, and the use of site-directed mutagenesis to produce a more stable protein species

Stability of Protein Pharmaceuticals

Nomenclature of Proteins of Cow's Milk: Fifth Revision

Substantial progress has been made in understanding the basic chemical and structural properties of the principal whey proteins, that is, beta-lactoglobulin (beta-Lg), alpha-lactalbumin (alpha-La), bovine serum albumin (BSA), and immunoglobulin (Ig) This knowledge has been acquired in terms of: (1) procedures for isolation, purification, and characterization of the individual whey proteins in buffer solutions; and (2) whey fractionation technologies for manufacturing whey protein concentrates (WPC) with improved chemical and functional properties in food systems This article is a critical review of selected publications related to (1) whey fractionation technology for manufacturing WPC and WPI; (2) fundamental properties of whey proteins; and (3) factors that affect protein functionality, that is, composition, protein structure, and processing

Whey protein concentrates and isolates: Processing and functional properties

The current state of the problem of protein folding is reviewed with special attention to the novel “molten globule” state of the protein molecule, intermediate between the native and unfolded states. Experimental evidence on the existence of this state and its role in protein folding are compared with the sequential model of protein folding proposed by the author in 1972–1973.

Protein folding: Hypotheses and experiments

α-Lactalbumin: A calcium metalloprotein

Bovine, human, and goat alpha-lactalbumins prepared by the ordinary methods were found to contain 1.1-1.3 atoms of Ca per protein molecule. Removal of Ca2+ was shown to destabilize the tertiary structures in the three proteins. The three apoproteins were indicated to change in the conformation by heat from the native-like to the unfolded state. Degree of restoration of the native tertiary structure in 5 mM Tris-HCl and 0.1 mM EDTA at pH 7.2 and 25 degrees C by addition of Ca2+ was determined from change in CD ellipticity at 270 nm, and the apparent binding constant of Ca2+ was analyzed to be 2.5 X 10(8) (bovine), 3.0 X 10(8) (human), and 2.8 X 10(8) M-1 (goat). Also, value of the binding constant of Ca2+ to the native-like apoform was estimated from the apparent binding constant and equilibrium constant of the conformational change of the apoform. The binding properties of Mn2+, Mg2+, and Zn2+ to the bovine protein at neutral pH are also discussed.

Interactions of Divalent Metal Ions with Bovine, Human, and Goat α-Lactalbumins

https://onlinelibrary.wiley.com/doi/pdf/10.1002/bip.1977.360160318

Tatsuhisa Segawa

Papers

α-Lactalbumin: A calcium metalloprotein

Interactions of Divalent Metal Ions with Bovine, Human, and Goat α-Lactalbumins

Application of stopped-flow circular dichroism to the study of the unfolding of proteins.

Kinetic correlations between the disulfide bond reduction and the induced conformational change of proteins