13472
We propose that a conformational mobility of the side - chains of Phe338 and His447 is a common feature in nerve - agent adducts of AChE .
 Chemical: Phe338; Chemical: His447
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Phe338; Chemical: His447