Antizyme inhibitor 2 (AZIN2)

Antizyme inhibitor 2 is a protein encoded by the AZIN2 gene in humans. It belongs to the antizyme inhibitor family, which functions primarily by regulating polyamine homeostasis—an essential process for cell growth and proliferation. AZIN2 is a non-enzymatic homolog of ornithine decarboxylase (ODC) and exerts its biological effects by binding to antizymes, thereby preventing them from inhibiting ODC and promoting polyamine uptake. In contrast to the ubiquitously-expressed antizyme inhibitor 1, antizyme inhibitor 2 shows tissue-specific expression, predominantly in the brain and testis, and is implicated in vesicular trafficking, secretion, and reproductive biology. While initially mischaracterized as arginine decarboxylase, it does not possess this enzymatic activity. Accumulation is reported in Alzheimer’s disease brains, and emerging research suggests a role in certain cancers and other diseases. No approved drugs currently target AZIN2 directly, but modulation of polyamine metabolism in general is an area of therapeutic interest

Other names

AZIN2AzI2AZI2Arginine decarboxylase (erroneous; this is a historical misnomer, as AZIN2 lacks arginine decarboxylase activity)

No approved or experimental drugs known to directly target antizyme inhibitor 2. Targeting the interaction between antizyme inhibitors and antizymes is proposed as a rationale for therapeutic intervention in polyamine-related processes, particularly cancer