23669
Methyl malonyl derivative 4 shows the highest binding affinity ( Ki = 2nM ) , analogues 5 , 7 , and 14 exhibit significant affinity for the kappa - receptor ( Ki = 21 , 36 and 39nM ) .
 Chemical: Methyl malonyl
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: Methyl malonyl