26299
S - nitrosation is a post - translational modification of protein cysteine residues which occurs in response to cellular oxidative stress .
 Chemical: S; Chemical: cysteine
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: S, cysteine 
Answer:
 Chemical: S; Chemical: cysteine