Competitive Elisa
Competitive Elisa - Related Videos
14:22
ELISA Assays: Indirect, Sandwich, and Competitive
0 Views •
2023
Source: Whitney Swanson1,2, Frances V. Sjaastad2,3, and Thomas S. Griffith1,2,3,4 1 Department of Urology, University of Minnesota, Minneapolis, MN 55455 2 Center for Immunology, University of Minnesota, Minneapolis, MN 55455 3 Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN 55455 4 Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455 Enzyme-linked immunosorbent assay (ELISA) is frequently used to measure the presence...
08:40
An ELISA Based Binding and Competition Method to Rapidly Determine Ligand-receptor Interactions
0 Views •
Cited by 40 •
2016
The presented protocols describe two enzyme-linked immunosorbent assay (ELISA) based techniques for the rapid investigation of ligand-receptor interactions: The first assay allows the determination of dissociation constant between ligand and receptor. The second assay enables a rapid screening of blocking peptides for ligand-receptor interactions.
10:06
The ELISA Method
0 Views •
2023
An enzyme-linked immunosorbent assay (ELISA) is typically performed to detect the presence and/or amount of a target protein of interest within an experimental sample. Detection of the target protein is made possible by antibodies, which make the ELISA an immunoassay. Through a series of incubation and washing steps, these antibodies, which are frequently linked, or conjugated, to an enzyme, will detect protein coating the bottom of a well on a microtiter plate. When exposed to a substrate,...
07:15
Measurement of Cyclic Guanosine Monophosphate (cGMP) in Solid Tissues using Competitive Enzyme-Linked Immunosorbent Assay (ELISA)
0 Views •
2025
This protocol measures cyclic guanosine monophosphate (cGMP) concentrations in solid tissues using competitive enzyme-linked immunosorbent assay (ELISA). The protocol describes how to process solid tissue, perform competitive ELISA, convert absorbances to cGMP concentrations in picomoles per milliliter, and calculate the final concentrations as nanomoles of cGMP per gram of tissue.
03:55
ELISA-Based Method to Analyze Interactions between Bait and Prey Proteins
0 Views •
2025
This video describes an ELISA-based technique that detects protein-protein interactions between two proteins by measuring the binding of the second protein to the immobilized first protein. The bound second protein is detected using specific antibodies labeled with an enzyme, such as horseradish peroxidase.
FAQs
The assay produces an inverse signal relationship: when more unlabeled analyte is present, it occupies more of the available binding capacity, leaving fewer labeled molecules captured. After washing, less enzyme remains associated with the assay, so the colorimetric signal falls. This inverse behavior allows signal intensity to indicate relative analyte concentration.
Limited binding sites create direct competition between the unlabeled analyte in a sample and a fixed amount of enzyme-labeled antigen or antibody. Both forms seek the same specific binding capacity, so their relative presence determines which becomes captured. Because the labeled component generates the detectable signal, changes in that balance affect the measured color intensity.
A molecule with a single available epitope cannot readily support the simultaneous binding arrangement required by some noncompetitive assay formats. Competitive ELISA instead measures how that molecule interferes with binding of a labeled counterpart to a specific antibody. This makes the format suitable for small molecules and other biological compounds with limited antigenic sites.
A typical workflow combines the sample, containing unlabeled analyte, with a fixed amount of enzyme-labeled antigen or antibody in the presence of specific binding sites. The competing components are allowed to interact, unbound material is removed by washing, and the retained enzyme produces a colorimetric signal. Signal intensity is then compared to analyte concentration.
Interpretation requires recognizing that stronger color does not indicate more analyte. A higher signal means that more labeled counterpart remained captured, which occurs when less unlabeled analyte competed for binding. Conversely, a weaker signal indicates greater competition and therefore a higher analyte concentration, supporting quantitative comparison across samples.
Competitive ELISA is suited to quantitative measurements of hormones, drugs, toxins, and other biological compounds when the target has a single available epitope or is otherwise appropriate for competition-based detection. Its ability to relate reduced enzyme signal to analyte concentration supports research, diagnostic, and quality-control applications in biology.