20531
To investigate this and solution - phase results with other tripeptides delta - ( L - alpha - aminoadipoyl ) - L - homocysteinyl - D - Xaa , we have crystallised AhCV and delta - ( L - alpha - aminoadipoyl ) - L - homocysteinyl - D - S - methylcysteine ( AhCmC ) with IPNS and solved crystal structures for the resulting complexes .
 delta - ( L - alpha - aminoadipoyl ) - L - homocysteinyl - D - Xaa, AhCV, delta - ( L - alpha - aminoadipoyl ) - L - homocysteinyl - D - S - methylcysteine, AhCmC
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 delta - ( L - alpha - aminoadipoyl ) - L - homocysteinyl - D - Xaa, AhCV, delta - ( L - alpha - aminoadipoyl ) - L - homocysteinyl - D - S - methylcysteine, AhCmC