9223
As catalysts , L - dipeptides containing a histidine residue , primarily Ser - His , were used .
 Chemical: L - dipeptides; Chemical: histidine; Chemical: Ser - 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: L - dipeptides, histidine, Ser - His 
Answer:
 Chemical: L - dipeptides; Chemical: histidine; Chemical: Ser - His