Target type: molecularfunction
Catalysis of the cleavage of the C-O-P bond in the AP site created when DNA glycosylase removes a damaged base, involved in the DNA base excision repair pathway (BER). [Wikipedia:AP_endonuclease]
DNA-(apurinic or apyrimidinic site) endonuclease activity, also known as AP endonuclease activity, is a critical function in DNA repair pathways. This activity is catalyzed by enzymes called AP endonucleases, which specifically recognize and cleave the phosphodiester backbone of DNA at abasic sites, also known as apurinic/apyrimidinic (AP) sites. These sites arise from spontaneous hydrolytic depurination or depyrimidination events, where a purine or pyrimidine base is lost from the DNA strand.
AP endonucleases play a key role in the base excision repair (BER) pathway, one of the major mechanisms for repairing damaged or modified DNA bases. The BER pathway involves the following steps:
1. **Recognition and Cleavage**: The AP endonuclease recognizes the AP site and cleaves the phosphodiester bond 5' to the abasic site, creating a 5' phosphate and a 3' hydroxyl group. This cleavage step generates a single-stranded DNA break, which facilitates further repair.
2. **Removal of AP Site**: Following cleavage, the 5' deoxyribose phosphate (dRP) residue, which remains attached to the 5' phosphate, is removed by a separate enzyme called dRP lyase.
3. **Gap Filling and Ligation**: The resulting single-stranded gap is then filled in by DNA polymerase, using the undamaged complementary strand as a template. Finally, the nick is sealed by DNA ligase.
By removing damaged or modified bases and restoring the integrity of the DNA sequence, AP endonuclease activity safeguards the genome from mutations and other harmful consequences. This activity is essential for maintaining the stability and functionality of the genetic code, ensuring the proper expression of genes and the accurate transmission of genetic information.
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| Protein | Definition | Taxonomy |
|---|---|---|
| Formamidopyrimidine-DNA glycosylase | A formamidopyrimidine-DNA glycosylase that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P05523] | Escherichia coli K-12 |
| Endonuclease 8-like 1 | An endonuclease 8-like 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q96FI4] | Homo sapiens (human) |
| DNA polymerase beta | A DNA polymerase beta that is encoded in the genome of human. [PRO:CNA] | Homo sapiens (human) |
| Endonuclease 8-like 1 | An endonuclease 8-like 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q96FI4] | Homo sapiens (human) |
| Endonuclease III-like protein 1 | An endonuclease III-like protein 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P78549] | Homo sapiens (human) |
| DNA-(apurinic or apyrimidinic site) endonuclease | A DNA-(apurinic or apyrimidinic site) endonuclease that is encoded in the genome of human. [PRO:DNx, UniProtKB:P27695] | Homo sapiens (human) |
| 40S ribosomal protein S3 | A eukaryotic-type small ribosomal subunit protein uS3 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P23396] | Homo sapiens (human) |
| DNA polymerase beta | A DNA polymerase beta that is encoded in the genome of human. [PRO:CNA] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| digallic acid | digallic acid: structure given in first source | benzoate ester; gallate ester | |
| aurintricarboxylic acid | aurintricarboxylic acid : A member of the class of quinomethanes that is 3-methylidene-6-oxocyclohexa-1,4-diene-1-carboxylic acid in which the methylidene hydrogens are replaced by 4-carboxy-3-hydroxyphenyl groups. The trisodium salt is the biological stain 'chrome violet CG' while the triammonium salt is 'aluminon'. Aurintricarboxylic Acid: A dye which inhibits protein biosynthesis at the initial stages. The ammonium salt (aluminon) is a reagent for the colorimetric estimation of aluminum in water, foods, and tissues. | monohydroxybenzoic acid; quinomethanes; tricarboxylic acid | fluorochrome; histological dye; insulin-like growth factor receptor 1 antagonist |
| hycanthone | hycanthone : A thioxanthen-9-one compound having a hydroxymethyl substituent at the 1-position and a 2-[(diethylamino)ethyl]amino substituent at the 4-position. It was formerly used (particularly as the monomethanesulfonic acid salt) as a schistosomicide for individual or mass treatement of infection with Schistosoma haematobium and S. mansoni, but due to its toxicity and concern about possible carcinogenicity, it has been replaced by other drugs such as praziquantel. Hycanthone: Potentially toxic, but effective antischistosomal agent, it is a metabolite of LUCANTHONE. | thioxanthenes | mutagen; schistosomicide drug |
| isoniazid | Hydra: A genus of freshwater polyps in the family Hydridae, order Hydroida, class HYDROZOA. They are of special interest because of their complex organization and because their adult organization corresponds roughly to the gastrula of higher animals. hydrazide : Compounds derived from oxoacids RkE(=O)l(OH)m (l =/= 0) by replacing -OH by -NRNR2 (R groups are commonly H). (IUPAC). | carbohydrazide | antitubercular agent; drug allergen |
| pamoic acid | pamoic acid: RN given refers to parent cpd; structure | dicarboxylic acid | |
| lucanthone | lucanthone : A thioxanthen-9-one compound having a methyl substituent at the 1-position and a 2-[(diethylamino)ethyl]amino substituent at the 4-position. Formerly used for the treatment of schistosomiasis. It is a prodrug, being metabolised to hycanthone. Lucanthone: One of the SCHISTOSOMICIDES, it has been replaced largely by HYCANTHONE and more recently PRAZIQUANTEL. (From Martindale The Extrapharmacopoeia, 30th ed., p46) | thioxanthenes | adjuvant; antineoplastic agent; EC 5.99.1.2 (DNA topoisomerase) inhibitor; EC 5.99.1.3 [DNA topoisomerase (ATP-hydrolysing)] inhibitor; mutagen; photosensitizing agent; prodrug; schistosomicide drug |
| Dillapiole | 5-allyl 6,7-dimethoxy 1,3-benzodioxole: a plant based insecticide; structure in first source | benzodioxoles | metabolite |
| oleanolic acid | hydroxy monocarboxylic acid; pentacyclic triterpenoid | plant metabolite | |
| zidovudine | zidovudine : A pyrimidine 2',3'-dideoxyribonucleoside compound having a 3'-azido substituent and thymine as the nucleobase. Zidovudine: A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by an azido group. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. The compound is a potent inhibitor of HIV replication, acting as a chain-terminator of viral DNA during reverse transcription. It improves immunologic function, partially reverses the HIV-induced neurological dysfunction, and improves certain other clinical abnormalities associated with AIDS. Its principal toxic effect is dose-dependent suppression of bone marrow, resulting in anemia and leukopenia. | azide; pyrimidine 2',3'-dideoxyribonucleoside | antimetabolite; antiviral drug; HIV-1 reverse transcriptase inhibitor |
| mitoxantrone hydrochloride | hydrochloride | antineoplastic agent | |
| ursolic acid | hydroxy monocarboxylic acid; pentacyclic triterpenoid | geroprotector; plant metabolite | |
| thymidine 5'-triphosphate | dTTP : A thymidine phosphate having a triphosphate group at the 5'-position. thymidine 5'-triphosphate: RN given refers to parent cpd | pyrimidine 2'-deoxyribonucleoside 5'-triphosphate; thymidine phosphate | Escherichia coli metabolite; mouse metabolite |
| betulinic acid | hydroxy monocarboxylic acid; pentacyclic triterpenoid | anti-HIV agent; anti-inflammatory agent; antimalarial; antineoplastic agent; EC 5.99.1.3 [DNA topoisomerase (ATP-hydrolysing)] inhibitor; plant metabolite | |
| calanolide a | (+)-calanolide A : An organic heterotetracyclic compound that is 11,12-dihydro-2H,6H,10H-dipyrano[2,3-f:2',3'-h]chromen-2-one substituted by a hydroxy group at position 12, methyl groups at positions 6, 6, 10 and 11 and a propyl group at position 4 (the 10R,11S,12S stereoisomer). Isolated from Calophyllum lanigerum var austrocoriaceum and Calophyllum brasiliense, it exhibits potent activity against HIV-1 reverse transcriptase. calanolide A: NSC 661122 and costatolide are isomers; a novel HIV-inhibitory class of coumarin derivatives from the tropical rainforest tree, Calophyllum lanigerum (Clusiaceae); structure in first source | cyclic ether; delta-lactone; organic heterotetracyclic compound; secondary alcohol | HIV-1 reverse transcriptase inhibitor; plant metabolite |
| 2',3'-dideoxythymidine triphosphate | ddTTP : A pyrimidine 2',3'-dideoxyribonucleoside 5'-triphosphate having thymine as the nucleobase. | pyrimidine 2',3'-dideoxyribonucleoside 5'-triphosphate; thymidine phosphate | |
| 2',3'-dideoxyadenosine triphosphate | purine deoxyribonucleoside triphosphate | ||
| zidovudine triphosphate | |||
| illimaquinone | illimaquinone: structure given in first source; isolated from the Red Sea sponge Smenospongia; inhibits the RNase H. activity of HIV-1 reverse transcriptase | monohydroxy-1,4-benzoquinones; prenylquinone | metabolite |
| 7-nitro-1h-indole-2-carboxylic acid | 7-nitro-1H-indole-2-carboxylic acid: acts on AP endonuclease, 3'-phosphodiesterase, and 3'-phosphatase activities of APE1; structure in first source | ||
| 3,3',4,4',5,5'-hexabromobiphenyl | |||
| 6-hydroxydopa | 6-hydroxydopa: RN given refers to cpd without isomeric designation | non-proteinogenic alpha-amino acid | |
| tanshinone ii a | tashinone IIA: a cardiovascular agent with antineoplastic activity; isolated from Salvia miltiorrhiza; structure in first source | abietane diterpenoid | |
| sitosterol, (3beta)-isomer | sitosterol : A member of the class of phytosterols that is stigmast-5-ene substituted by a beta-hydroxy group at position 3. Sobatum: tradename; active fraction of Solanum trilobatum; reduces side-effects of radiation-induced toxicity | 3beta-hydroxy-Delta(5)-steroid; 3beta-sterol; C29-steroid; phytosterols; stigmastane sterol | anticholesteremic drug; antioxidant; mouse metabolite; plant metabolite; sterol methyltransferase inhibitor |
| TTP | pyrimidine ribonucleoside 5'-triphosphate | ||
| aphidicolin | aphidicolin : A tetracyclic diterpenoid that has an tetradecahydro-8,11a-methanocyclohepta[a]naphthalene skeleton with two hydroxymethyl substituents at positions 4 and 9, two methyl substituents at positions 4 and 11b and two hydroxy substituents at positions 3 and 9. An antibiotic with antiviral and antimitotical properties. Aphidicolin is a reversible inhibitor of eukaryotic nuclear DNA replication. Aphidicolin: An antiviral antibiotic produced by Cephalosporium aphidicola and other fungi. It inhibits the growth of eukaryotic cells and certain animal viruses by selectively inhibiting the cellular replication of DNA polymerase II or the viral-induced DNA polymerases. The drug may be useful for controlling excessive cell proliferation in patients with cancer, psoriasis or other dermatitis with little or no adverse effect upon non-multiplying cells. | tetracyclic diterpenoid | antimicrobial agent; antimitotic; antineoplastic agent; antiviral drug; apoptosis inducer; Aspergillus metabolite; DNA synthesis inhibitor; EC 2.7.7.7 (DNA-directed DNA polymerase) inhibitor; fungal metabolite |
| 1,3,6-trimethylpyrimido[5,4-e][1,2,4]triazine-5,7-dione | pyrimidotriazine | ||
| 2-[[5-(dimethylsulfamoyl)-1H-indol-3-yl]methylidene]propanedioic acid diethyl ester | indoles | ||
| 1,6-dimethyl-3-propylpyrimido[5,4-e][1,2,4]triazine-5,7-dione | pyrimidotriazine | ||
| stigmasterol | stigmasta-5,22-dien-3-ol: isolated from freeze-dried powder of Blackberries (Rubus ursinus L.) which showed an activity on inhibition of chemocarcinogen stigmasterol : A 3beta-sterol that consists of 3beta-hydroxystigmastane having double bonds at the 5,6- and 22,23-positions. | 3beta-hydroxy-Delta(5)-steroid; 3beta-sterol; phytosterols; stigmastane sterol | plant metabolite |
| myricetin | 7-hydroxyflavonol; hexahydroxyflavone | antineoplastic agent; antioxidant; cyclooxygenase 1 inhibitor; food component; geroprotector; hypoglycemic agent; plant metabolite | |
| ag 538 | AG 538: an IGF-1 receptor kinase inhibitor; structure in first source | ||
| lyoniside | daucosterol : A steroid saponin that is sitosterol attached to a beta-D-glucopyranosyl residue at position 3 via a glycosidic linkage. It has bee isolated from Panax japonicus var. major and Breynia fruticosa. | beta-D-glucoside; monosaccharide derivative; steroid saponin | plant metabolite |
| e 3330 | E 3330: structure given in first source; MW 378.47 | ||
| corosolic acid | triterpenoid | metabolite | |
| gentamicin sulfate | |||
| edgeworin | edgeworin: from Dirca occidentalis Gray; structure given in first source | ||
| N-[3-(1,3-benzothiazol-2-yl)-5,6-dihydro-4H-thieno[2,3-c]pyrrol-2-yl]acetamide | benzothiazoles | ||
| raltegravir | 1,2,4-oxadiazole; dicarboxylic acid amide; hydroxypyrimidine; monofluorobenzenes; pyrimidone; secondary carboxamide | antiviral drug; HIV-1 integrase inhibitor | |
| GS-443902 | GS-441524 triphosphate: intracellular active metabolite of remdesivir GS-443902 : An organic triphosphate that is GS-441524 in which the 5'-hydroxy group has been replaced by a triphosphate group. It is the active metabolite of remdesivir. | aromatic amine; C-nucleoside; nitrile; organic triphosphate; pyrrolotriazine | anticoronaviral agent; antiviral drug; drug metabolite |
| PF-06446846 | PF-06446846 : A triazolopyridine that is 3H-[1,2,3]triazolo[4,5-b]pyridine substituted by a 4-{(3-chloropyridin-2-yl)[(3R)-piperidin-3-yl]carbamoyl}phenyl group at position 3. It is a potent inhibitor of PCSK9. PF-06446846: inhibits translation of PCSK9 ;structure in first source | benzamides; monochloropyridine; piperidines; tertiary carboxamide; triazolopyridine | antilipemic drug; EC 3.4.21.61 (kexin) inhibitor |
| thiolactomycin | thiolactomycin: from actinomycetes; structure given in first source | ||
| galloflavin | galloflavin: structure in first source |