19498
His ' s protonation state can vary near physiological pH , and a probe of His ' s variable protonation state and its resulting noncovalent interactions that has both high time resolution and no sample limitations could find wide use in determining the role of particular His residues in proteins .
 Chemical: His; Chemical: His; Chemical: His
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: His, His, His 
Answer:
 Chemical: His; Chemical: His; Chemical: His