8901
Previous studies have shown that binding to cell-surface heparan sulphate is essential for optimal activity of IFN-gamma and that free heparin competitively inhibits this sequestration process .
 ( protein: IFN-gamma, 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: IFN-gamma, None) 