11452
IFN - alpha 2a was incorporated in hydrogels composed of hyaluronic acid - tyramine ( HA - Tyr ) conjugates through the oxidative coupling of Tyr moieties with hydrogen peroxide ( H2O2 ) and horseradish peroxidase ( HRP ) .
 Chemical: tyramine; Chemical: Tyr; Chemical: Tyr; Chemical: hydrogen peroxide; Chemical: H2O2
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: tyramine; Chemical: Tyr; Chemical: Tyr; Chemical: hydrogen peroxide; Chemical: H2O2