22731
Biophysical fragment screening of a thermostabilized beta 1 - adrenergic receptor ( beta 1AR ) using surface plasmon resonance ( SPR ) enabled the identification of moderate affinity , high ligand efficiency ( LE ) arylpiperazine hits 7 and 8 .
 arylpiperazine
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 arylpiperazine