DNA-(apurinic or apyrimidinic site) lyase (APEX1)
Links to databases
Multifunctional protein that plays a central role in the cellular response to oxidative stress. The two major activities of APEX1 in DNA repair and redox regulation of transcriptional factors. Functions as a apurinic/apyrimidinic (AP) endodeoxyribonuclease in the DNA base excision repair (BER) pathway of DNA lesions induced by oxidative and alkylating agents. Initiates repair of AP sites in DNA by catalyzing hydrolytic incision of the phosphodiester backbone immediately adjacent to the damage, generating a single-strand break with 5'-deoxyribose phosphate and 3'-hydroxyl ends. Does also incise at AP sites in the DNA strand of DNA/RNA hybrids, single-stranded DNA regions of R-loop structures, and single-stranded RNA molecules. Has a 3'-5' exoribonuclease activity on mismatched deoxyribonucleotides at the 3' termini of nicked or gapped DNA molecules during short-patch BER. Possesses a DNA 3' phosphodiesterase activity capable of removing lesions (such as phosphoglycolate) blocking the 3' side of DNA strand breaks. May also play a role in the epigenetic regulation of gene expression by participating in DNA demethylation. Acts as a loading factor for POLB onto non-incised AP sites in DNA and stimulates the 5'-terminal deoxyribose 5'-phosphate (dRp) excision activity of POLB. Plays a role in the protection from granzymes-mediated cellular repair leading to cell death. Also involved in the DNA cleavage step of class switch recombination (CSR). On the other hand, APEX1 also exerts reversible nuclear redox activity to regulate DNA binding affinity and transcriptional activity of transcriptional factors by controlling the redox status of their DNA-binding domain, such as the FOS/JUN AP-1 complex after exposure to IR. Involved in calcium-dependent down-regulation of parathyroid hormone (PTH) expression by binding to negative calcium response elements (nCaREs). Together with HNRNPL or the dimer XRCC5/XRCC6, associates with nCaRE, acting as an activator of transcriptional repression. Stimulates the YBX1-mediated MDR1 promoter activity, when acetylated at Lys-6 and Lys-7, leading to drug resistance. Acts also as an endoribonuclease involved in the control of single-stranded RNA metabolism. Plays a role in regulating MYC mRNA turnover by preferentially cleaving in between UA and CA dinucleotides of the MYC coding region determinant (CRD). In association with NMD1, plays a role in the rRNA quality control process during cell cycle progression. Associates, together with YBX1, on the MDR1 promoter. Together with NPM1, associates with rRNA. Binds DNA and RNA.
Recommended sample types are human EDTA plasma and serum. A range of additional sample types are compatible with the technology (PEA), including citrate plasma, heparin plasma, cerebrospinal fluid, (CSF), tissue and cell lysates, fine needle biopsis, microdialysis fluid, cell culture media, dried blood spots, synovial fluid, saliva, plaque extract and microvesicles. Please note that protein expression levels are expected to vary in different sample types. Certain assays are differentially affected by interfering substances such as hemolysate. Download any of our Data Validation documents or contact firstname.lastname@example.org for more information.
NOTE: The calibrator curve below shows the performance of the assay with the estimated sensitivity and dynamic range parameters indicated. These curves are generated during the assay validation process using recombinant antigens. Please note that when analyzing biological samples the data generated will be given in the form of relative quantification (NPX values) and cannot be converted to absolute protein concentrations. For more info about NPX measurements, please visit our FAQ page.
Analytical Measuring Range
Please note: the technical data reported below refers to the measured value in the in vitro validation assays. Since the Metabolism panel uses human samples diluted 10-fold, a multiplication factor of 10 should be applied when comparing the addressable biological concentration to this validation data.
Calibrator curve for validation data (generated in multiplex)
- Within run precision Coefficient of Variation (CV)
- Between run precision Coefficient of Variation (CV)
Precision (repeatability) is calculated from linearized NPX values over LOD.
Biomarker Validation Data
Additional validation data, as well as a more detailed description of how the Olink panels are quality controlled can be found in our Data Validation documents. To download or to learn more go to the Data Validation page.