25371
Elastin - mimetic protein polymers were prepared in which noncanonical amino acid derivatives were incorporated at up to 22 specific sites within the polypeptide sequence with high substitution efficiency .
 Chemical: amino acid
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