Methylated polyamines derivatives and antizyme-related effects.

Antizyme is a key regulator of polyamine homeostasis, and the biosynthesis of this short-lived protein is induced in response to the increase of the intracellular polyamine concentration. Once synthesized, antizyme inhibits polyamine transport and directs the ODC subunit to the 26S proteasome, that normalize the polyamine pool in the cell. Here we demonstrated that polyamines induce dimerization of full-length mouse antizyme with the formation of (antizyme)₂-polyamine complex. This can be modulated by C-methylated analogues of spermidine and functionally active 2-methylspermidine turned to be a very poor inducer unlike spermidine and its other C-methylated analogues. The protocols for gram-scale synthesis of C-methylated spermidines and for detecting antizyme dimerization using isothermal titration calorimetry and electrophoresis are described.