The proximity extension assay (PEA) is a method for detecting and quantifying the amount of many specific proteins present in a biological sample such a serum or plasma.[1] The method is used in the research field of proteomics, specifically affinity proteomics,[2] where in one searches for differences in the abundance of many specific proteins in blood for use as a biomarker. Biomarkers and biomarker signature combinations, are useful for determining disease states[3] and drug efficacy.[4] Most methods for detecting proteins involve the use of a solid phase for first capturing and immobilizing the protein analyte, where in one or a few proteins are quantified, such as ELISA. In contrast, PEA is performed without a solid phase in a homogeneous one tube reaction solution where in sets of antibodies coupled to unique DNA sequence tags, so called proximity probes, work in pairs specific for each target protein. PEA is often performed using antibodies and is a type of immunoassay. Target binding by the proximity probes increases their local relative effective concentration of the DNA-tags enabling hybridization of weak complementarity to each other which then enables a DNA polymerase mediated extension forming a united DNA sequence specific for each target protein detected. The use of 3'exonuclease proficient polymerases lowers background noise and hyper thermostable polymerases mediate a simple assay with a natural hot-start reaction. This created pool of extension products of DNA sequence forms amplicons amplified by PCR where each amplicon sequence corresponds to a target proteins identity and the amount reflects its quantity. Subsequently, these amplicons are detected and quantified by either real-time PCR or next generation DNA sequencing by DNA-tag counting. PEA enables the detection of many proteins simultaneously (so called multiplexing) due to the readout requiring the combination of two correctly bound antibodies per protein to generate a detectable DNA sequence from the extension reaction.[5] Only cognate pairs of sequence are detected as true signal, enabling multiplexing beyond solid phase capture methods limited at around 30 proteins at a time.[6] The DNA amplification power also enable minute sample volumes even below one microliter. PEA has been used in over 1000 research publications.[7][8]
^Lundberg, M.; Eriksson, A.; Tran, B.; Assarsson, E.; Fredriksson, S. (2011). "Homogeneous antibody-based proximity extension assays provide sensitive and specific detection of low-abundant proteins in human blood". Nucleic Acids Research. 39 (15): e102. doi:10.1093/nar/gkr424. PMC 3159481. PMID 21646338.
^Smith, J. Gustav; Gerszten, Robert E. (2017). "Emerging Affinity-Based Proteomic Technologies for Large-Scale Plasma Profiling in Cardiovascular Disease". Circulation. 135 (17): 1651–1664. doi:10.1161/CIRCULATIONAHA.116.025446. PMC 5555416. PMID 28438806.
^Fredriksson, S.; Dixon, W.; Ji, H.; Koong, A. C.; Mindrinos, M.; Davis, R. W. (2007). "Multiplexed protein detection by proximity ligation for cancer biomarker validation". Nature Methods. 4 (4): 327–329. doi:10.1038/nmeth1020. PMID 17369836. S2CID 1902394.
The proximityextensionassay (PEA) is a method for detecting and quantifying the amount of many specific proteins present in a biological sample such...
Incorporated's Infinium assay is an example of a whole-genome genotyping pipeline that is based on primer extension method. In the Infinium assay, over 100,000...
Fisher Scientific acquired Olink. Olink Proteomics devised the Proximityextensionassay (PEA) technology, a protein biomarker research tool used across...
spectrometry-based proteomics studies, published immune assay data and a longitudinal study based on proximityextensionassay (PEA). Further, an analysis of the “human...
for proteins. The protein content of lysates can be measured by proximityextensionassays (PEA), for example, which use DNA-barcoded antibodies. A different...
technology was subsequently developed by Hoffmann-La Roche for diagnostic assays and by Applied Biosystems (now part of Thermo Fisher Scientific) for research...
approach, and the use of this approach is not recommended when repeated assays from the same sample is required. Additionally, the one-step approach is...
of regulation, inspection and enforcement, e.g. the Goldsmiths' Company Assay Office, while others are awarding bodies for professional qualifications...
product. Occasionally, an assay fails and approaches are essential to resurrect a failed assay. The most sensitive enzyme assays use lasers focused through...
chemical properties of nucleic acids using specific reagents and conditions to assay the structure of nucleic acids. Such methods may involve chemical probing...
2011). "Development and validation of a real-time polymerase chain reaction assay" (PDF). Journal of Veterinary Diagnostic Investigation. 24 (1): 135–137...
mutations in Adenomatous Polyposis Coli promote tumorigenesis. A novel assay, Fast parallel proteolysis (FASTpp), might help swift screening of specific...
Sabin–Feldman dye test (DT), the indirect hemagglutination assay, the indirect fluorescent antibody assay (IFA), the direct agglutination test, the latex agglutination...
notorious for harming unsuspecting civilians. The immunochromatographic assay would eliminate the need for expensive, time-consuming lab tests and enable...
incoming alpha male to prevail over the previous male. There are genetic assays being scheduled for lions to determine their genetic diversity. The preliminary...
Denver Instrument Company in 1895 to make analytical balances for gold assayers. Its factory is now in Arvada. AIMCO (NYSE: AIV)—the largest owner and...
oospores were isolated, cleaned, and stained with tetrazolium dye in the MTT assay. Purple oospores were counted as dormant whereas clear, blue, or black were...
damage to skyscrapers that were lighted up from top to bottom. ... The Assay Office, nearest the point of explosion, naturally suffered the most. The...
(December 2012). "A novel non-radioactive primase-pyrophosphatase activity assay and its application to the discovery of inhibitors of Mycobacterium tuberculosis...
detectable for 2–4 days. For the assays, a study noted that an enzyme multiplied immunoassay technique (EMIT) assay for amphetamine and methamphetamine...
Global Information