Adenine was first discovered in 1885 by the German physiologist Albrecht Kossel. He isolated adenine from the pancreas of oxen and named it "adenine" derived from the Greek word "aden," meaning gland.

In the double helix structure of DNA, thymine forms a base pair with adenine through two hydrogen bonds ... 5-Methylcytosine is a modified nucleobase formed by the enzymatic addition of a methyl group ...