| Abstract: | The acid denaturation of ribonuclease-A and lysozyme in 8 M urea has been studied by nuclear magnetic resonance (N.M.R.) spectroscopy and gel chromatography and compared with previous ultraviolet difference spectroscopic and viscometric studies. The N.M. R. results show that lysozyme is completely unfolded below pH 3 and virtually native at pH > 3.5 whereas Sigma ribonuclease-A is completely unfolded below pH 5 and about 60% native at pH 7. These results obtained at a protein concentration of 10% are consistent with the qualitative conclusions obtained by the other techniques in much more dilute solutions. The NMR method is an attractive procedure for rapid exploration of a range of solution conditions in order to find the best set of conditions for the separation of a mixture of proteins in the random coil form (I). |
