3898
NPT II synthesis , measured by agar plate assays of kanamycin resistance and by immunoprecipitation of the NPT II protein , was repressed in the presence of cysteine and derepressed in its absence .
 NPT II, NPT II protein
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 NPT II, NPT II protein