19598
To understand better this significant loss of activity , enzymatic assays and molecular modeling were carried out and suggested 2 ' - C - methyl - 6 - O - methyl - 7 - deaza guanosine and related ProTides do not act as efficient prodrugs of the free nucleotide , in marked contrast to the case of the parent guanine analogue .
 Chemical: 2 ' - C - methyl - 6 - O - methyl -; Chemical: guanosine; Chemical: nucleotide; Chemical: guanine
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: 2 ' - C - methyl - 6 - O - methyl -, guanosine, nucleotide, guanine 
Answer:
 Chemical: 2 ' - C - methyl - 6 - O - methyl -; Chemical: guanosine; Chemical: nucleotide; Chemical: guanine