11733
Moreover, the inhibitors of serine proteases , N-alpha-tosyl-L-lysine chloromethyl ketone and N-alpha-tosyl-L-phenylalanine chloromethyl ketone , also blocked the cytolytic activity of NK cells against the sensitive target K562 .
 ( protein: serine proteases, None) , ( cell type: NK cells, None) , ( cell line: K562, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: serine proteases, None) , ( cell type: NK cells, None) , ( cell line: K562, None) 