Effect of crystalline abrin on the biosynthesis of protein, RNA, and DNA in experimental tumors.

Crystalline abrin isolated from Abrus precatorius L. has been shown to have a strong inhibitory effect on the protein biosynthesis of Ehrlich ascites tumor and Yoshida ascites hepatoma cells and a moderate inhibitory effect on the DNA biosynthesis of these neoplastic cells. It has no significant effects on the RNA biosynthesis and cellular respiration of these neoplastic cells at a much higher concentration of abrin than that required for curing the tumor. The inhibitory effect of abrin was not significantly changed by addition of glucose. By heating the solution of abrin at 100°for 30 min, the inhib