THE DENATURED STATES OF RIBONUGLEASE II

Abstract

Denatured pancreatic ribonuclease has previously been shown to exist in three well-defined states, which are probably sequentially related. All denaturants studied, with one exception, were shown to convert native ribonuclease (N) to one or other of these denatured states (I, II, and III). The exception was very concentrated (~9 M) lithium bromide, which appeared to give another denatured state (IV) with some properties the same as those of II, and some the same as those of III. We have now carried out a thorough investigation of this apparent state IV, by difference spectroscopy and polarimetry. We find that the earlier results were misleading, and in fact that there is no conformation change II → IV, so that we can write a denaturation pathway for ribonuclease simply as: [Formula: see text].