5727
Mass spectroscopy revealed that two Trp residues , Trp84 in the CAS , and Trp279 in the PAS , were the only Trp residues , out of a total of 14 , significantly modified by photo - oxidation , both being converted to NFK .
 Trp, Trp84, Trp279, Trp, NFK
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Trp, Trp84, Trp279, Trp, NFK