16523
We employed this method to establish a bead - based peptide array containing 384 peptides displaying phosphorylated , acetylated , methylated , and citrullinated N - terminal regions of histones H2A , H2B , H3 and H4 and controls .
 Chemical: N
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: N 
Answer:
 Chemical: N