29270
Formation of the key precursor anhydrotetracycline 3 during oxytetracycline 1 biosynthesis has been previously characterized .
 anhydrotetracycline, oxytetracycline
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 anhydrotetracycline, oxytetracycline