Intramolecular chaperones and protein folding.

Many proteins from both prokaryotic and eukaryotic sources are produced with amino-terminal propeptides. These propeptides, which are usually located between the signal peptide and the mature protein, are essential for the proper function of that protein. Recent research has indicated that these polypeptides are indispensible for proper folding of the proteins they are attached to. As propeptides perform a function similar to that of a large family of heat shock proteins, they had been broadly classified as molecular chaperones. However, significant differences exist between these two classes of proteins and to distinguish them from one another, propeptides have been termed intramolecular chaperones. Recent results have suggested that such intramolecular chaperones may be found in a large number of proteins.