Disease relevance of europium

• In MeOH, lysophosphatidic acid (LPA), a biomarker for several pathological conditions including ovarian cancer, is selectively detected by the europium complex [1].
• The europium binding properties of both unfractionated E. coli tRNA and purified tRNA-fMet are quite similar, indicating that the location of the strong binding sites and their binding constants are nearly the same for a large group of tRNA [2].
• CONCLUSION: Neonatal screening for congenital toxoplasmosis can be automated by use of purified europium-labeled antigen for detection of T. gondii-specific IgM and IgA eluted from filter-paper samples [3].
• The human MUC1 mucin, as determined by a europium-based immunoradiometric assay, was detected in the serum of 9/11 animals that showed histological evidence of brain metastases [4].
• METHODS: Streptavidin-coated microtiter plates were incubated with biotinylated GAD65, and after incubation with serum samples from patients with type 1 diabetes mellitus and control individuals, europium-labeled GAD65 was added [5].

High impact information on europium

• The europium complex detects sialic acid-containing gangliosides at pH 7.0 over an asialoganglioside [1].
• The complexes were assayed by time-resolved immunofluorometric assays based on an antibody against PSA on the solid phase and europium-labeled antibodies against various protease inhibitors as indicator antibodies [6].
• Anti-c-Myc monoclonal antibody (mAb 9-E10) derivatized with a fluorophore (europium cryptate, EuK) was used to individually label c-Myc-tagged alpha1-, beta2-, or gamma2-subunits of the hetero-oligomeric gamma-aminobutyric acid (GABAA) receptor in intact cells [7].
• The distance was measured by fluorescence energy transfer using a novel europium chelate as a fluorescence donor [8].
• Oncomodulin and parvalbumin. A comparison of their interactions with europium ion [9].

Chemical compound and disease context of europium

• Binding of the first 3-4 europium ions is independent and sequential, approximately 600 times stronger than the magnesium binding, and the binding sites are located near the 4-thiouridine residue found at position 8 in a number of E. coli tRNA [2].
• The biotinylated PCR products were collected on streptavidin-coated microtitration wells and hybridized with short oligonucleotide probes, europium labeled for HSV-1 and samarium labeled for HSV-2 [10].
• The test used polystyrene beads coated with rubella antigen as the solid phase and a chelate of the rare earth metal europium as fluorescent label [11].
• The specimens were dispensed with europium and terbium labelled antibodies against adenovirus and rotavirus, respectively, to coated microtitration strip wells [12].
• Toxicity study of europium chloride in rats [13].

Biological context of europium

• The hydroxide-dependent hydrolysis rate in the europium complex is about 10(5) times that of free substrate with hydroxide [14].
• The scissile phosphate of the substrate is displaced from its normal position by about 1 A when Eu3+ is bound and the presence of Eu3+ in the active site precludes the binding of the essential metal ion B [15].
• These alamethicin channels were found to permit the outward passage of europium ions into the extravesicular medium when the transmembrane potential is more positive for the inner compartment [16].
• Polymerase chain reaction (PCR) was performed on the appropriate region of the apoB gene, and the PCR products were hybridized in solution with europium-labeled oligonucleotides, complementary to either the wildtype or the mutant genome [17].
• Europium-labeled oligonucleotides to detect point mutations: application to PIZ alpha 1-antitrypsin deficiency [18].

Anatomical context of europium

• Decreased skeletal muscle phosphotyrosine phosphatase (PTPase) activity towards insulin receptors in insulin-resistant Zucker rats measured by delayed Europium fluorescence [19].
• NK cell activity was measured in a 4-h nonisotopic assay with europium-labeled and cryopreserved K-562 cells [20].
• An improved, luminescent europium-based stain for detection of electroblotted proteins on nitrocellulose or polyvinylidene difluoride membranes [21].
• Lateral Flow Immunoassay Using Europium (III) Chelate Microparticles and Time-Resolved Fluorescence for Eosinophils and Neutrophils in Whole Blood [22].
• To evaluate the functional activity of these antibodies, a highly sensitive europium release assay was used to compare complement-mediated cytolysis of human melanocytes by sera of 56 patients with vitiligo (20 with active disease, 25 with inactive disease, 11 with unidentified disease activity) and 47 control individuals [23].

Associations of europium with other chemical compounds

• The specific hybrids were labelled after filter hybridization with europium ions through the chelating groups of DTPA [24].
• In addition, the europium and terbium cations have the useful property that their luminescence is enhanced when bound to nucleic acids [25].
• Furthermore, Eu3+ does not support catalysis by KF exo or several other two-metal-ion phosphoryl-transfer enzymes [15].
• This time-resolved immunofluorometric assay for human follitropin involves use of europium- or samarium-labeled monoclonal antibodies, with an average incorporation ratio of 3 mol of Eu3+ or Sm3+ per mole of antibody [26].
• Spectra of the fluorescent chelates in the microtitration-strip wells were run on a time-resolved fluorometer equipped with filters for Eu3+ (613 nm) and Sm3+ (643 nm), the fluorescence from each sample being inversely proportional to the concentration of antigens [27].

Gene context of europium

• The assay consists of FLAG-tagged ERalpha or ERbeta ligand binding domain (LBD), a biotinylated coactivator peptide, europium-labeled anti-FLAG antibody, and streptavidin-conjugated allophycocyanin [28].
• Upon agonist binding, the biotinylated coactivator peptide is recruited to FLAG-tagged ER LBD to form a complex and thus allow fluorescence resonance energy transfer (FRET) to occur between europium and allophycocyanin [28].
• The sensitivity, stability, and high specific activity of europium-labeled IL8 demonstrate the usefulness of lanthanide-labeled proteins in the measurement of receptor-ligand interactions and may be extended to other peptide ligands [29].
• Robust FRET was observed when an 18-amino-acid APP Swedish-synthetic peptide that was N-terminally labeled with europium cryptate and C-terminally biotinylated was incubated with streptavidin-coupled cross-linked allophycocyanin (SA-XL665) [30].
• We designed a simple homogeneous time-resolved fluorescence (HTRF) assay which utilizes the fluorescence resonance energy transfer (FRET) pair europium and allophycocyanin for measuring BACE1 enzymatic activity in a high-throughput manner [30].

Analytical, diagnostic and therapeutic context of europium

• Using a novel europium-based class I MHC-peptide binding immunoassay, we determined that MT236-244 bound Dk 2-3 logs less well than MT389-397 [31].
• The europium ions were quantitatively detected by time-resolved fluorometry [24].
• The assay includes PCR amplification of a fragment encompassing the mutation site followed by hybridization reactions with allele-specific europium (Eu)-labelled oligonucleotide probes [32].
• Third, this protocol is evaluated for a noncompetitive immunoassay of a human immunoglobulin G, and a concentration as low as 3.1 x 10(-12) M is determined, which is competitive with colloidal gold-based anodic stripping voltammetry (ASV), colorimetric ELISA, or immunoassays based on fluorescent europium chelate labels [33].
• Streptavidin-polyvinylamine conjugates labeled with a europium chelate: applications in immunoassay, immunohistochemistry, and microarrays [34].

References