HYDROGEN-EXCHANGE AT EQUILIBRIUM - A SHORT-CUT FOR ANALYZING PROTEIN-FOLDING PATHWAYS

Hydrogen exchange is an attractive method for observing small populati ons of partly unfolded states of proteins at equilibrium. It has been suggested that these represent folding intermediates so that hydrogen exchange can offer a short cut for studying protein-folding pathways. This cannot work in theory because it is not possible to tell whether they are intermediates or side reactions. Experimental studies of barn ase and chymotrypsin inhibitor 2 show that there is no obvious relatio nship between hydrogen exchange at equilibrium and their folding pathw ays.