23851
Both compounds 1 and 2 were found to promote early infection events in HIV , likely by inhibiting the enzyme indolamine 2 , 3 - dioxygenase ( IDO ) and preventing tryptophan depletion .
 Chemical: indolamine; Chemical: tryptophan
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: indolamine, tryptophan 
Answer:
 Chemical: indolamine; Chemical: tryptophan