Target type: molecularfunction
Catalysis of the removal of purines present in mismatches, especially opposite oxidized purines, by cleaving the N-C1' glycosidic bond between the target damaged DNA base and the deoxyribose sugar. The reaction releases a free base and leaves an apurinic (AP) site. [GOC:elh, PMID:9224623]
Purine-specific mismatch base pair DNA N-glycosylase activity is a critical enzyme involved in DNA repair, specifically targeting mismatched base pairs within DNA. Its primary function is to excise damaged or mismatched purine bases (adenine or guanine) from the DNA duplex, preventing the propagation of errors during DNA replication and transcription. This enzymatic activity proceeds through a specific mechanism:
1. **Recognition and Binding:** The enzyme recognizes and binds to the mismatched base pair in DNA. This recognition involves precise interactions between the enzyme's active site and the mismatched bases, ensuring specificity for purine-containing mismatches.
2. **Base Excision:** The enzyme cleaves the N-glycosidic bond between the damaged or mismatched purine base and the deoxyribose sugar within the DNA backbone. This reaction results in the removal of the purine base, leaving an apurinic/apyrimidinic (AP) site in the DNA.
3. **Product Release:** The excised purine base and the enzyme are released from the DNA. The AP site is then further processed by other DNA repair enzymes, ultimately leading to the restoration of the correct DNA sequence.
Purine-specific mismatch base pair DNA N-glycosylases play a crucial role in maintaining genomic integrity by removing potentially harmful mutations. Their activity is essential for preventing the accumulation of DNA damage and ensuring accurate DNA replication and transcription. Defects in these enzymes are associated with increased susceptibility to cancer and other genetic disorders.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Proliferating cell nuclear antigen | A proliferating cell nuclear antigen that is encoded in the genome of human. [PRO:DNx] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 3,3',5-triiodothyroacetic acid | tiratricol : A monocarboxylic acid that is (4-hydroxy-3,5-diiodophenyl)acetic acid in which the phenolic hydroxy group has been replaced by a 4-hydroxy-3-iodophenoxy group. It is a thyroid hormone analogue that has been used in the treatment of thyroid hormone resistance syndrome. | ||
| 3,3',5-triiodothyropropionic acid | aromatic ether | ||
| thyroxine | thyroxine : An iodothyronine compound having iodo substituents at the 3-, 3'-, 5- and 5'-positions. Thyroxine: The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism. | 2-halophenol; iodophenol; L-phenylalanine derivative; non-proteinogenic L-alpha-amino acid; thyroxine; thyroxine zwitterion | antithyroid drug; human metabolite; mouse metabolite; thyroid hormone |
| triiodothyronine | 3,3',5-triiodo-L-thyronine : An iodothyronine compound having iodo substituents at the 3-, 3'- and 5-positions. Although some is produced in the thyroid, most of the 3,3',5-triiodo-L-thyronine in the body is generated by mono-deiodination of L-thyroxine in the peripheral tissues. Its metabolic activity is about 3 to 5 times that of L-thyroxine. The sodium salt is used in the treatment of hypothyroidism. Triiodothyronine: A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3. | 2-halophenol; amino acid zwitterion; iodophenol; iodothyronine | human metabolite; mouse metabolite; thyroid hormone |
| 3,5-diiodothyronine, (l)-isomer | phenylalanine derivative | ||
| 3,3'-diiodothyronine | 3,3'-diiodothyronine: RN given refers to unlabeled cpd without isomeric designation | 3,3'-diiodothyronine; amino acid zwitterion | human metabolite |
| 3,5-diiodothyropropionic acid | 3,5-diiodothyropropionic acid : A monocarboxylic acid that is (4-hydroxy-3,5-diiodophenyl)propanoic acid in which the phenolic hydroxy group has been replaced by a 4-hydroxyphenyl group. An ionotropic analogue of L-thyroxine. 3,5-diiodothyropropionic acid: a cardiotonic thyroid hormone analog | aromatic ether; monocarboxylic acid; organoiodine compound; phenols |