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Subsequently chemical mutagenesis completely converted the cysteine into gamma - thialysine through dehydroalanine ( Dha ) as demonstrated by ESI - MS .
 cysteine, gamma - thialysine, dehydroalanine, Dha
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 cysteine, gamma - thialysine, dehydroalanine, Dha