4638
Comparative analysis of four oxidized guanine lesions from reactions of DNA with peroxynitrite , singlet oxygen , and gamma - radiation .
 Chemical: guanine; Chemical: peroxynitrite; Chemical: oxygen
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: guanine; Chemical: peroxynitrite; Chemical: oxygen