Glycosylase

Glycosylases belong to the hydrolases family. Hydrolases hydrolytically cleave ester, ether, peptide, glycoside and other bonds. Examples are esterases, phosphatases or proteases. Glycosylases enzymatically remove glycosyl components from various substrates. The respective enzymes are named after the substrate to which they have affinity.

DNA glycosylases, for example, belong to a family of DNA repair enzymes that are able to recognize and repair DNA damage. They are an important part of the base excision repair of the cell.

In detail, the different DNA glycosylases recognise damaged bases and remove them from their deoxyribose phosphate scaffold. This creates an AP site in the DNA (apyrimidine or apurine site). An endonuclease can now open the DNA strand at the defective site and remove the deoxyribose. A DNA polymerase synthesizes the correct base depending on the complementary base on the faultless strand. A DNA ligase links the new base in the DNA strand, thus correcting the error.

In the MUTYH-associated polyposis, for example, there is a mutation in the MUTYH gene (MYH gene) on chromosome 1p34.1. The MUTYH gene encodes a glycosylase, which is located in the cell nucleus and the mitochondria of the cell and specifically repairs DNA damage.