1435
We present molecular modeling of the structure and possible proton transfer pathways from the surface of the protein to the zinc - bound water molecule in the active site of the mutant His - 107 - Tyr of human carbonic anhydrase II ( HCAII ) .
 Chemical: zinc; Chemical: His; Chemical: Tyr
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: zinc; Chemical: His; Chemical: Tyr