depyrimidination

Definition

Target type: biologicalprocess

The disruption of the bond between the sugar in the backbone and the C or T base, causing the base to be removed and leaving a depyrimidinated sugar. [GOC:ai]

Depyrimidination is a chemical reaction that removes a pyrimidine base (cytosine or thymine) from a DNA molecule. This process can be spontaneous or induced by various agents, including ionizing radiation, alkylating agents, and certain enzymes.

Spontaneous depyrimidination occurs due to the inherent instability of the glycosidic bond that links the base to the deoxyribose sugar. This bond can break due to thermal fluctuations, leading to the loss of the base and the formation of an abasic site.

Depyrimidination can also be induced by various agents, such as ionizing radiation, which can directly damage the DNA molecule. Alkylating agents can also cause depyrimidination by modifying the base, making it more susceptible to removal.

Some enzymes, such as uracil DNA glycosylase (UNG), are involved in depyrimidination. UNG specifically removes uracil from DNA, which can arise from the deamination of cytosine.

Depyrimidination can have significant biological consequences. The loss of a base from DNA can lead to mutations, as the DNA polymerase may insert the wrong base during replication. Additionally, abasic sites can be highly mutagenic, as they can trigger double-strand breaks in the DNA.

Depyrimidination plays a role in various biological processes, including DNA repair, mutagenesis, and aging. The repair of depyrimidinated DNA is essential for maintaining the integrity of the genome and preventing the accumulation of mutations.'
"

Proteins (6)

Compounds (5)