Enzyme Inhibition Assay
Enzyme Inhibition Assay - Related Videos
08:11
Measuring Influenza Neuraminidase Inhibition Antibody Titers by Enzyme-linked Lectin Assay
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Cited by 54 •
2016
We describe the enzyme-linked lectin assay (ELLA) for measuring influenza neuraminidase (NA)-inhibition antibody titers in sera. The assay uses peanut agglutinin to quantify galactose residues that become accessible when NA removes sialic acid from fetuin-coated, 96-well plates.
01:30
Enzyme Inhibition
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2025
Inhibitors are molecules that reduce enzyme activity by binding to the enzyme. In a normally functioning cell, enzymes are regulated by a variety of inhibitors. Drugs and other toxins can also inhibit enzymes. Some inhibitors bind to the enzyme’s active site, while others inhibit enzymatic activity by binding to other sites on the protein structure. Competitive inhibitors occupy the active site of enzymes, making them unable to accommodate the substrate. However, sufficiently high...
08:07
Enzyme Assays and Kinetics
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2023
Enzyme kinetics describes the catalytic effects of enzymes, which are biomolecules that facilitate chemical reactions necessary for living organisms. Enzymes act on molecules, referred to as substrates, to form products. Enzyme kinetic parameters are determined via assays that directly or indirectly measure changes in substrate or product concentration over time. This video will cover the basic principles of enzyme kinetics (including rate equations) and kinetic models. The concepts governing...
03:47
Microscopic Assessment of Enzyme-Mediated Inhibition of Biofilm Formation
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2026
Source: Tay, S. B., et.al. Anti-virulent Disruption of Pathogenic Biofilms using Engineered Quorum-quenching Lactonases. J. Vis. Exp. (2016)This video demonstrates the process of inhibiting biofilm formation by introducing an enzyme that disrupts bacterial cell signaling. The enzyme prevents the bacteria from producing extracellular polymeric substances, thereby reducing biofilm development on a glass-bottomed microdish. Finally, the biofilm structure is visualized using fluorescent lectins and...
03:19
An Assay to Measure Influenza Neuraminidase Inhibition Antibody Titers
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2025
This video demonstrates an assay measuring influenza neuraminidase (NA) inhibiting antibody titers in a serum sample. A serum sample containing antibodies against NA is added to a fetuin-coated microwell plate. Upon adding the virus, the antibodies prevent viral NA from cleaving fetuin and exposing its galactose moiety. A peroxidase-conjugated lectin is then added, which binds to the exposed galactose. The NA-inhibiting antibody titer is determined using a colorimetric test, where a peroxidase...
FAQs
Competitive inhibition occurs when an inhibitor interferes with substrate binding at the enzyme, whereas other inhibitory effects may act through different regulatory mechanisms. Comparing assay results across substrate or inhibitor concentrations helps distinguish these possibilities. This distinction matters because it connects the observed reduction in catalytic activity with the molecular interaction responsible for that change.
Varying substrate and inhibitor levels reveals how strongly the compound affects enzyme activity under different conditions. Substrate changes can help identify interference with substrate binding, while inhibitor changes show the concentration dependence of the response. Together, these measurements support characterization of inhibition potency and help separate a specific kinetic effect from a general reduction in activity.
The uninhibited control establishes the enzyme’s activity without the test compound, providing the reference for evaluating inhibition. Researchers compare product formation or another activity-linked signal from treated samples with this baseline. Without that comparison, a measured signal cannot be confidently attributed to the inhibitor rather than to the enzyme’s normal catalytic behavior or assay conditions.
A typical workflow defines the enzyme, substrate, and inhibitor concentrations, then measures substrate conversion or a signal linked to product formation. Parallel samples include an uninhibited control, and inhibitor levels can be varied to assess concentration-dependent effects. Comparing the resulting activity measurements allows researchers to estimate inhibition potency and investigate the underlying kinetic pattern.
Researchers apply these assays when they need to connect a compound’s molecular interaction with a measurable change in enzyme function. In biochemistry, the method supports kinetic analysis, drug discovery, toxicology, and investigations of metabolic pathways. The resulting activity data can help evaluate candidate compounds, examine potentially harmful effects, or clarify how regulation influences biochemical processes.
By showing how a compound changes the activity of a selected enzyme, the assay provides evidence about that enzyme’s contribution to a metabolic pathway. Comparing inhibition strength and kinetic behavior can indicate how molecular regulation may alter pathway function. This biochemical context helps researchers relate an isolated enzyme response to broader biological outcomes without measuring the entire pathway directly.