Inhibitors of polyamine biosynthesis. 3. (+/-)-5-Amino-2-hydrazine-2-methylpentanoic acid, an inhibitor of ornithine decarboxylase.

(+/-)-5-Amino-2-hydrazino-2-methylpentanoic acid [alpha-hydrazino-alpha-methyl-(+/-)-ornithine] was obtained from 1-phthalimidopentan-4-one by treatment with hydrazine and KCN followed by acid hydrolysis. The title compound was found in vitro to be a potent competitive inhibitor of ornithine decarboxylase obtained from the prostate glands of rats. This inhibition was abolished at high concentrations of pyridoxal phosphate. The title compound also blocked the increase in putrescine levels normally observed in bovine lymphocytes transformed by conconavalin A.