9891
Upon activation by phenobarbital , nuclear receptor CAR binds the 97 - bp response element ( - 2441 / - 2345 ) within the Kcnk1 promoter .
 Chemical: phenobarbital
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: phenobarbital