26647
In - silico docking studies based on the crystal structure of the PR ligand - binding domain show that , in contrast to progesterone , APR19 does not establish stabilizing hydrogen bonds with the ligand binding cavity , resulting in an unstable ligand - receptor complex .
 Chemical: progesterone; Chemical: APR19; Chemical: hydrogen
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: progesterone, APR19, hydrogen 
Answer:
 Chemical: progesterone; Chemical: APR19; Chemical: hydrogen