This article describes research into the conformational stability of globular proteins -- specifically the effects of various electrolytes and nonelectrolytes on the thermally induced structural transition in ribonuclease. Optical rotatory methods were used to measure transition parameters including: melting temperature (T m ), the size of the transition (DELTA(alpha)), its breadth, and the specific optical rotation and optical rotary dispersion of the pre- and post-transition compounds. Structural perturbants investigated were neutral salts (with and without ethylene glycol), urea and the guanidinium salts, the tetraalkylammonium ions and the alcohols. Physicochemical instrumental analysis methods used in the study include polarimetry, viscometry, ultraviolet (UV) spectroscopy, short column sedimentation (weight average molecular weights); spectrophotometry and interferometry were used to characterize the bovine pancreatic ribonuclease used for most of the experiments.
Hippel et al. (1965) studied this question.