Polyamines inhibit the protein kinase 380--catalyzed phosphorylation of eukaryotic initiation factor 2 alpha.

Polyamines putrescine, spermidine, and spermine specifically inhibit the PK 380--catalyzed phosphorylation of eukaryotic initiation factor 2 alpha (eIF-2 alpha). Since te PK 380--dependent phosphorylation of eIF-2 alpha inhibits the initiation or protein synthesis, the possibility exists that the polyamines enhance protein synthesis by inhibiting the phosphorylation of eIF-2 alpha by PK 380.