This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Most important amino acid for formation Neutrophilic extracellular trap (NET) is 
Select and explain. 
A. Leucine, B. Methionine, C. Citrulline, D. Valine
C: Citrulline
Answer: C: Citrulline 
Explanation: Conversion of arginine residues to Citrulline in the histones is an essential step in the formation of neutrophill extracillular traps.