The best replacement for adenine is adenosine.

The best alternatives to adenine are rated as following:
★★★★★  adenosine
★★★  guanine
★  thymine
  atp

Your alternative for adenine is not listed? Suggest!
Speaking about adenine, one probably shouldn't forget about thymine.

Other search terms related to adenine and their ratings are:
★★★★★ thymine
★★★★ uracil
You have in mind a companion for adenine and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of adenine in all years. Click on graph for more.
adenine
adenosine
guanine