16248
The results of SOS screening in our optimised E . coli reporter strain SOS - R2 were generally predictive of the ability of nitroreductase candidates to sensitise E . coli to CB1954 , and of the kcat / Km for each prodrug substrate at a purified protein level .
 CB1954
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 CB1954