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Recently , it has been proposed to couple an enzymatic activation step based on horseradish peroxidase ( HRP ) / hydrogen peroxide to such peptide reactivity assays .
 Chemical: hydrogen peroxide
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: hydrogen peroxide