8728
Here we show that drug - specific differences in receptor internalization are determined by a conserved , 10 - residue sequence in the receptor ' s carboxyl - terminal cytoplasmic tail .
 Chemical: carboxyl
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: carboxyl 
Answer:
 Chemical: carboxyl