Fluorometric Enzyme Assay
Fluorometric Enzyme Assay - Related Videos
12:33
High-throughput Fluorometric Measurement of Potential Soil Extracellular Enzyme Activities
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Cited by 485 •
2013
To measure potential rates of soil extracellular enzyme activities, synthetic substrates that are bound to a fluorescent dye are added to soil samples. Enzyme activity is measured as the fluorescent dye is released from the substrate by an enzyme-catalyzed reaction, where higher fluorescence indicates more substrate degradation.
07:37
Click-Chemistry Based Fluorometric Assay for Apolipoprotein N-acyltransferase from Enzyme Characterization to High-Throughput Screening
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Cited by 2 •
2020
Presented here is a sensitive fluorescence assay to monitor apolipoprotein N-acyltransferase activity using diacylglyceryl peptide and alkyne-phospholipids as substrates with click-chemistry.
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...
05:29
Measuring Caspase Activity Using a Fluorometric Assay or Flow Cytometry
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Cited by 6 •
2023
The present protocol describes two methods to measure caspase activity through a fluorogenic substrate using flow cytometry or a spectrofluorometer.
03:27
Insoluble Chromogenic Biomass-Based Enzyme Screening: An Assay to Evaluate the Degradation Activity of Plant Biomass-Degrading Enzymes
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2025
This video demonstrates an assay to screen enzymes effective in degrading complex polysaccharides in plant biomass using insoluble chromogenic biomass or ICB. The enzymes hydrolyze ICB to release soluble dye-linked oligosaccharides, and the enzyme activity is assessed by colorimetric analysis of the reaction product.
FAQs
Under controlled reaction conditions, greater fluorescence generally indicates that more fluorescent product has formed. Because product formation reflects enzyme catalysis, the measured signal can be used to compare catalytic rates between samples. This relationship is most useful when assay conditions remain consistent, allowing differences in fluorescence to be interpreted as differences in enzyme activity rather than uncontrolled reaction changes.
The assay depends on measuring fluorescence at selected excitation and emission wavelengths suited to the fluorescent substrate or product. Excitation provides the energy needed to generate the fluorescent signal, while emission measurement captures the resulting light. Choosing and maintaining the specified wavelength settings helps the instrument detect the reaction signal consistently across samples and experimental comparisons.
A fluorogenic substrate provides the chemical link between enzyme catalysis and fluorescence detection. When the enzyme converts this substrate, a fluorescent product is generated, creating a measurable signal that increases with product formation. This design allows enzyme activity to be followed through fluorescence rather than relying only on direct measurement of substrate disappearance or product accumulation by another method.
Reaction conditions must be controlled because fluorescence is interpreted as a measure of product formed and catalytic activity. If conditions vary between samples, signal differences may not reflect enzyme behavior alone. Consistent conditions therefore support more reliable comparisons of catalytic responses, inhibitor effects, enzyme concentrations, and other biochemical factors examined with the assay.
A basic workflow includes combining the enzyme sample with a fluorogenic substrate, allowing the reaction to proceed under controlled conditions, and measuring fluorescence at selected excitation and emission wavelengths. The resulting signal is then used to assess product formation and enzyme activity. Microplate readers can support this workflow across multiple samples, enabling systematic comparisons within one experiment.
These assays provide fluorescence measurements that can be related to product formation and catalytic rate, making them useful for examining enzyme kinetics. Researchers can compare how rapidly different samples generate signal under defined reaction conditions. The approach is especially valuable when enzyme abundance is low or when many reactions must be evaluated consistently using a microplate format.
In inhibitor screening, enzyme activity is compared across reactions containing different samples or inhibitory conditions. A change in fluorescence indicates a corresponding change in fluorescent product formation and therefore a change in catalytic response, provided the assay conditions remain controlled. This makes the method useful for identifying and comparing effects on enzyme activity across multiple test conditions.
Microplate readers allow fluorescence measurements from many assay samples in a compatible format, supporting efficient comparison of enzyme activity, concentrations, inhibitors, or reaction conditions. Their use also suits analyses involving low-abundance enzymes because the assay can detect fluorescence generated by the reaction product. The resulting measurements help researchers compare catalytic responses across multiple biochemical samples.