In the present study we show that the oligomerization of the proteolytic products is an intrinsic property of prion proteins. No such oligomerization was observed for the proteolytic products of other proteins after identical treatment. The rate of enzymatic hydrolysis of recombinant human (rhPrP) (23-231) and golden hamster (rmaPrP) (23-231) prion proteins as well as that of rmaPrP (90-231), corresponding to the infectious fragment of the scrapie form, drastically increases in the presence of chemical chaperones like dimethyl sulphoxide and glycerol as well as in 20% ethanol. A bacterial proteinase, termed "prionase," has a superior efficiency towards prion proteins in comparison to proteinase K and subtilisin DY. The early steps in the proteolysis by the latter enzymes have been identified. The results have potential impact on the treatment of scrapie-infected materials.