Effect of ascorbate oxidase on radical intensity and cytotoxic activity of ascorbate.

In order to test whether ascorbyl radical can directly induce apoptotic cell death, it was produced by the reaction of sodium L-ascorbate with L-ascorbate oxidase. Sodium L-ascorbate induced cytotoxicity against both human glioblastoma and promyelocytic leukemic cell lines. The addition of ascorbate oxidase significantly enhanced both degradation and radical generation of ascorbate, but completely eliminated its cytotoxic activity against both of these cells. These data demonstrate that the ascorbyl radical is not the sole determinant of apoptosis induction.