29619
The synthetic APF provided a platform to study amino acid modifications and their effect on APF activity , based on which a structure - activity relationship ( SAR ) for APF activity was previously proposed .
 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