14508
From alchemical mutation calculations , we find that methylation of one of the cytosines increases the free energy of the extra - helical conformation by 10 . 3 - 16 . 5 kJ / mol and this increase is additive with respect to the second methylation .
 cytosines
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 cytosines