Physico-chemical studies on bovine γ-globulin

Abstract 1. 1. Fluorescence depolarisation measurements on bovine γ-globulin in neutral solution yield rotational relaxation times which are much lower than expected from the translational dynamic properties of the molecule. Only a small further reduction in the relaxation time is caused by the presence of 6 M urea. 2. 2. With the simple dispersion, low λ c (2130 A) and − b 0 values obtained from optical-rotation measurements over a range of wavelengths, it is suggested that nonpolar amino acid residues may be of importance in controlling internal folding within the core of the molecule but that a considerable measure of internal flexibility still remains outside this core. 3. 3. The action of LiBr on bovine γ-globulin is complex. In addition to the small change in optical-rotatory properties at low LiBr concentrations, an opposite trend, probably involving denaturation, occurs at higher LiBr concentrations. Beyond 5 M LiBr, a considerable reduction in solubility is observed.