25530
We have developed a methodology for quantitative analysis and concurrent identification of proteins by the modification of cysteine residues with a combination of iodoacetanilide ( IAA , 1 ) and ( 13 ) C7 - labeled iodoacetanilide ( ( 13 ) C7 - IAA , 2 ) , or N - ethylmaleimide ( NEM , 3 ) and d5 - labeled N - ethylmaleimide ( d5 - NEM , 4 ) , followed by mass spectrometric analysis using nano liquid chromatography / nanoelectrospray ionization ion trap mass spectrometry ( nano LC / nano - ESI - IT - MS ) .
 cysteine, iodoacetanilide, IAA, ( 13 ) C7, iodoacetanilide, ( 13 ) C7, IAA, N - ethylmaleimide, NEM, d5, N - ethylmaleimide, d5, NEM
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 cysteine, iodoacetanilide, IAA, ( 13 ) C7, iodoacetanilide, ( 13 ) C7, IAA, N - ethylmaleimide, NEM, d5, N - ethylmaleimide, d5, NEM