The Interdependence of Substrate and Protein Transformations in Rhodanese Catalysis

Two catalytically inert conformers of rhodanese have been observed. One arises from a slow autoconversion of the free enzyme and can be induced to a catalytically active form by the substrate, thiosulfate ion. The other results upon reaction of the free enzyme with the inhibitors, iodoacetate and sulfite ions. The inert conformers can be related to dimeric forms of the enzyme protein. Release of the bound sulfur atom from the sulfur-substituted enzyme intermediate has been detected in the absence of the cyanide ion acceptor substrate.