26302
C47 of GSTP1 - 1 is S - nitrosated in two steps , with the chemical step limited by a pre - equilibrium between the open and closed conformations of helix alpha 2 at the active site .
 S
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 S