21102
We used whole - cell recordings of human embryonic kidney cells heterologously expressing either wild - type TRPA1 or TRPA1 with three serine - substituted cysteines crucial for electrophile activation ( C621S , C641S , C665S ) .
 Chemical: serine; Chemical: cysteines
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: serine; Chemical: cysteines