CPP32 has been recently reported to be involved in the early process of programmed cell death. To further study CPP32 and its regulation in the cell, a 830 bp cDNA was cloned by RT-PCR from CNE cells encoding the full length human CPP32 protein and high level expression was achieved in E.coli by using GST expression system. The results showed that the bacterially expressed CPP32 protein is auto-cleaved and capable of cleaving in vitro-translated PARP, thus is fully functional.