16900
Herein we discuss quaternary structure dynamics aspects to drug discovery for the disease - associated putative morpheeins phenylalanine hydroxylase , HIV integrase , pyruvate kinase , and tumor necrosis factor alpha .
 phenylalanine, pyruvate
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 phenylalanine, pyruvate