20780
In vitro studies with new non - toxic read - through agents as well as in vivo studies would also be essential to determine the extent of read - through required to restore normal phenylalanine levels .
 Chemical: phenylalanine
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: phenylalanine