Although evidence has been mounting since the 1930s that proteins could be reversibly denatured, it was not until the 1960s that the elegant experiments of Anfinsen on bovine pancreatic Ribonuclease A (RNase A) established that all the information needed for a protein to acquire three-dimentional structure is contained in its aminoacid sequence (1 ). However, the code that yields a fully folded protein from a string of amino acids has not been deciphered yet.