12253
BChE inhibited by authentic , racemic tabun yielded both 902 . 2 and 874 . 2 m / z peptides , indicating that both stereoisomers reacted with BChE and aged either by deamination or dealkylation .
 Chemical: racemic tabun
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: racemic tabun