5546
We investigated the inhibitory action of six flavonoids on IkappaB kinase ( IKK ) activity, an enzyme recently found to phosphorylate critical serine residues of IkappaB for degradation.
 IKK, IkappaB kinase
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 IKK, IkappaB kinase