1510
The native enzyme purified from protease - B - deficient URA2 - transformed cells , was phosphorylated in vitro using catalytic subunits of pure cAMP - dependent protein kinase .
 protease - B, URA2, cAMP - dependent protein kinase
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 protease - B, URA2, cAMP - dependent protein kinase