6862
Analogous to the active site of Zn ( 2 + ) carboxypeptidases , calnuc has two high affinity ( K ( d ) ~ 20 nm ) , well conserved Zn ( 2 + ) - binding sites near its N terminus , although it is inactive as a peptidase .
 Chemical: Zn ( 2 + ); Chemical: Zn ( 2 + ); Chemical: N
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: Zn ( 2 + ), Zn ( 2 + ), N 
Answer:
 Chemical: Zn ( 2 + ); Chemical: Zn ( 2 + ); Chemical: N