30348
We report a new , facile , fluorescence - based assay for the detection of PAD4 activity that exploits the substrate specificity of trypsin to monitor the citrullination reaction carried out by PAD4 based on the fact that , upon citrullination , the positively charged arginine side chain is converted to the neutral citrulline .
 Chemical: trypsin; Chemical: citrulline
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: trypsin, citrulline 
Answer:
 Chemical: trypsin; Chemical: citrulline