Structure-toxicity Relationship in Subunit Structure of Ricin D

Abstract

The re-formation of the single disulfide bond which linked two polypeptide chains of ricin D was studied. Ricin D was reoxidized preferentially by the air-oxidation of its reduced polypeptide chains in a yield of 74% with the recovery of full toxicity. Furthermore ricin D was completely regenerated from its compound with p-chloromercuribenzoate. It seems reasonable to assume that the toxicity of ricin D arises from the quaternary structure of ricin D molecule.