19931
Molecular modeling studies concluded that recognition with key amino acid Arg38 and Lys31 are essential for binding and biological activities .
 Chemical: amino acid; Chemical: Arg38; Chemical: Lys31
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: amino acid; Chemical: Arg38; Chemical: Lys31