CHAPERONE-LIKE ACTIVITY OF PROTEIN DISULFIDE-ISOMERASE IN THE REFOLDING OF RHODANESE

Protein disulfide-isomerase (PDI) in near stoichiometric concentration s promotes reactivation and prevents aggregation of guanidine-hydrochl oride-denatured rhodanese during refolding upon dilution. PDI also sup presses aggregation of rhodanese during thermal inactivation. The abov e-mentioned properties displayed by PDI completely satisfy the definit ion of chaperone and provide additional evidence to confirm the hypoth esis proposed previously [Wang, C. C. & Tsou, C. L. (1993) FASEB J. 7, 1515-1517] that PDI is both an enzyme and a chaperone. Since rhodanes e contains no disulfide bonds, the chaperone-like activity of PDI acti ng on rhodanese is independent of its disulfide-isomerase activity.