Depyrimidation
The Depyrimidierung is a DNA damage in which a pyrimidine base ( cytosine or thymine ) from the sugar phosphate backbone of the DNA double strand by hydrolysis is cleaved. The phosphodiester skeleton remains intact during these processes, but this can lead to single strand breaks in a DNA strand. The depyrimidation takes place predominantly via the deamination route . A cytosine residue is deaminated to form a uracil . The deamination of adenine in hypoxanthine is far less common . As soon as uracil binds to adenine or hypoxanthine binds to cytosine, a mutation results . A uracil in the DNA sequence is quickly recognized and eliminated by DNA repair mechanisms , since uracil is not part of DNA. The uracil-DNA glycosylase can remove uracil from DNA.