Why depyrimidination doesnot occur?

Answer 1

I'm still looking for a good answer to this one. I've actually read that it does occur but at a much slower frequency than depurination. Apparently, the depyrimidination frequency is around 500 pyrimidines per cell per day as opposed to 10,000 depurinations per cell per day. It seems counterintuitive really, when you think of the steric hindrance the water would encounter when attacking the glycosidic bond of a large purine double ring vs. the same force experienced near the smaller pyrimidine single ring.

Answer 2

Depyrimidination, the removal of a pyrimidine base from DNA or RNA, does not occur naturally because pyrimidines are essential for the stability and function of nucleic acids. If depyrimidination were to occur, it would result in significant damage to the genetic material, compromising the integrity of the genome and potentially leading to cell death or mutations.