7555
Exchange of domains between the two isoforms indicates that the C1b domain and the N - terminus of the C1a domain are important for directing selective regulation of AC7 by the G ( 13 ) pathway .
 Chemical: N
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: N