Reduction and RE-oxidation of the purothionins

The disulphide bonds of the purothionins have been fully reduced with 2‐mercaptoethanol. Starch‐gel electrophoresis of the products and also of the reduced proteins after blocking with acrylonitrile confirms previous tentative evidence that purothionins a and 0 both consist of single polypeptide chains. Reduced purothionin doublet has been re‐oxidised under various conditions, the major finding being that in dilute solution re‐formation of structure predominates whereas in very concentrated solution, extensive intermolecular cross linking appears to occur.