19130
Remarkably , the formation of six stereocenters and the regiospecific formation of six rings in A - 74528 appear to be catalyzed by only two tailoring enzymes , a cyclase and an oxygenase , in addition to the core polyketide synthase .
 A - 74528
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 A - 74528