12250
A scheme to distinguish aging by deamination from aging by O - dealkylation was based on the acid labile P - N bond .
 Chemical: O; Chemical: P - N
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: O; Chemical: P - N