13557
There were two mutation sites in AFE _ 1073 between DY26 and DC and one may change the hydrophobicity of AFE _ 1073 , which could enhance the ability of DY26 to pump out Cu ( + ) .
 Cu ( + )
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Cu ( + )