Abstract
Two constituent polypeptide chains of native or iodinated ricin D were separated by affinity chromatography on Sepharose 4 B after reduction with β-mercaptoethanol, and purified by DEAE-cellulose column chromatography.
The hybrid molecule between the native Ile chain and the iodinated Ala chain was easily formed by reduction-reoxidation of a mixture of both isolated chains. Its toxicity to mice was about 20% of that of ricin D and about ten fold that of the iodinated ricin D.
On the other hand, the hybrid molecule between native Ala chain and maleyl Ile chain was obtained by reduction-reoxidation of a mixture of native and maleyl ricin D, and its toxicity to mice was about 15% of that of ricin D and about four fold that of maleyl ricin D.
These results suggest that tyrosine and lysine residues in each chain of ricin D are involved in the toxic action of ricin D.
