13780
To investigate further, we then purified a number of different kinases, including PKC , PhK , ZAP-70 , ERK , and MEK 1 (a MKK ), and showed that Ro 09-2210 was a selective inhibitor of MEK1 in vitro (IC50 = 59 nM).
 ( protein: MKK, None) , ( protein: MEK1, None) , ( protein: ZAP-70, None) , ( protein: MEK 1, None) , ( protein: ERK, None) , ( protein: PKC, None) , ( protein: PhK, 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: MKK, None) , ( protein: MEK1, None) , ( protein: ZAP-70, None) , ( protein: MEK 1, None) , ( protein: ERK, None) , ( protein: PKC, None) , ( protein: PhK, None) 