21001
Dissociation constants for Na ( + ) and Ca ( 2 + ) with the oxidized enzyme were 1 . 2 mM and 11 mu M , respectively and Na ( + ) binding appeared to involve cooperative binding of two Na ( + ) .
 Chemical: Na ( + ); Chemical: Ca ( 2 + ); Chemical: Na ( + ); Chemical: Na ( + )
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: Na ( + ); Chemical: Ca ( 2 + ); Chemical: Na ( + ); Chemical: Na ( + )