嘌呤碱基的C8来自于 A N5—CH—NH—FH4B N5—CH3—FH4C N10—CHO—FH

嘌呤碱基的C8来自于

A N5—CH—NH—FH4

B N5—CH3—FH4

C N10—CHO—FH4

D N5, N10—CH2—FH4

E N5, N10 = CH—FH4