21005
This was attributed to the difficulty in fully depleting Ca ( 2 + ) from its binding site , as has been found with bacterial CcOs .
 Chemical: Ca ( 2 + )
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Ca ( 2 + )