Antizyme is a polyamine-induced cellular protein that binds to ornithine decarboxylase (ODC), and targets it to rapid ubiquitin-independent degradation by the 26S proteasome. However, the metabolic fate of antizyme is not clear. We have tested the stability of antizyme in mammalian cells. In contrast with previous studies demonstrating stability in vitro in a reticulocyte lysate-based degradation system, in cells antizyme is rapidly degraded and this degradation is inhibited by specific proteasome inhibitors. .
