Abstract: AimTo find a convenient and highly effective cell-free apoptotic system and investigate the apoptotic process of mouse liver nuclei in the system and the inhibitory effects of z-VAD-fmk on apoptosis. MethodsThe cell-free system was prepared by ultracentrifugation of Xenopus eggs and activated by cytochrome C. Fluorescent microscope, argrose gel electrophoresis and apoalert Caspase-3 colorimetric assay were applied to detect the apoptotic process of isolated nuclei and the inhibitory effecs of z-VAD-fmk on the system. Results The prepared cell-free system was shown to be activated by cytochrome C. The exogenous mouse liver nuclei presented typical morphologic changes and DNA ladder formation was observed which could be inhibited by z-VAD-fmk. Specific endonuclease was activated and XCPP32 activity was significantly increased in the system. ConclusionThe prepared cell-free apoptotic system can effectively induce isolated nuclei apoptosis and mimick the process in vivo.