3794
We have successfully adapted an approach , using fusion proteins of GPCRs and chimeric G proteins , to create an in vitro screening assay ( in human embryonic kidney cells ) in which only activated heteromers are detectable .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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