In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

 In addition , caspase - 3 , an executioner of apoptosis , was activated and its substrate , poly ( ADP - ribose ) polymerase ( PARP ) , was cleaved during 2 , 2 ' , 4 , 6 , 6 ' - PeCB - induced apoptosis .
caspase - 3