8501
Utilizing domain - specific antibodies coupled with N - terminal sequencing , it was confirmed that both forms contained the C - terminal module of the protein core known as endorepellin , which were generated by mast cell - derived proteases .
 N, C
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 N, C