21466
Ser - 796 and Glu - 797 are part of a loop ( residues 795 - 803 ) that closes over the active site .
 Chemical: Ser; Chemical: Glu
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: Ser; Chemical: Glu