Enzyme Conjugation
Enzyme Conjugation - Related Videos
02:57
Enzyme-Linked Immunosorbent Assay to Verify Chemically-Coupled Antibody-Antigen Conjugates
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2025
This video demonstrates the detection of chemically conjugated antibody-antigen complexes via the sandwich enzyme-linked immunosorbent assay, or ELISA, technique. The captured antibody binds to the specific epitope of the antigen of the antibody-antigen conjugate, which can be later visualized using an enzyme-linked secondary antibody.
02:50
Conjugated Proteins
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2020
Simple proteins and protein complexes contain only amino acids. In contrast, many other proteins, called conjugated proteins, covalently bond with non-protein moieties. Nucleoproteins are protein complexes that contain nucleic acids, categorized as deoxyribonucleoproteins (DNPs) or ribonucleoproteins (RNPs) respectively. The nucleosome is a typical example of a DNP where nuclear DNA is associated with histone proteins. The major antigen for the Covid-19 virus SARS-CoV is an RNP that is critical...
02:34
Enzymes
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2020
Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions. Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
01:19
Conjugation
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2025
Conjugation is a form of horizontal gene transfer that primarily occurs in bacteria and some archaea, promoting genetic diversity and adaptation. Bacteria can acquire resistance genes through conjugative plasmids, allowing them to survive antibiotic treatments that would otherwise be lethal. This process involves direct contact between cells through specialized structures such as the sex pilus and is mediated by conjugative plasmids, including the F (fertility) factor.Conjugation requires...
04:35
Enzyme Activity - Concepts
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2019
Biological Catalysts All living organisms continuously perform numerous biochemical reactions to sustain their presence. Most of these reactions require an input of energy to start, which is called the activation energy. Catalysts are chemicals that lower the activation energy. Even though catalysts facilitate a chemical reaction, they are not consumed by it. This means a catalyst can facilitate a specific chemical reaction over and over in succession, increasing the rate of that reaction.
FAQs
The key design challenge is forming a stable covalent attachment without disrupting the enzyme’s structure or activity. Crosslinking connects functional groups on the enzyme and its partner, creating a durable conjugate. When the enzyme remains active, the attached molecule can still generate a detectable or useful catalytic response, which supports reliable biological measurements.
Chemical crosslinkers provide a molecular route for joining existing functional groups, whereas engineered reactive groups introduce designed attachment sites. Both approaches aim to create stable bonds, but they represent different ways of controlling attachment. This distinction matters because the conjugate must retain the enzyme’s structure and activity while linking it to its selected partner.
Successful attachment depends on balancing bond stability with preservation of function. If the enzyme’s structure or activity is not maintained, the conjugate may lose the catalytic property that makes it useful. The identity of the partner, whether an antibody, nucleic acid, or nanoparticle, also determines the selective targeting or detection role added to the enzyme.
Combining catalytic activity with selective targeting can strengthen biological signals. An attached enzyme can produce a measurable color or light signal after converting a substrate, while its partner contributes molecular selectivity. This division of roles is especially important when detecting a particular biological target, because catalytic signal generation and target-directed binding operate together.
At a conceptual level, preparation involves selecting the enzyme and partner, choosing a chemical crosslinker or engineered reactive group, and forming covalent bonds between compatible functional groups. The resulting conjugate must then be considered in terms of retained enzyme structure and activity. These steps connect molecular design with the intended detection or targeting function.
Antibodies add selective binding, nucleic acids provide a biologically relevant molecular partner, and nanoparticles offer a particulate platform for combining enzyme activity with detection or targeting. The choice depends on the intended tool: antibody-based conjugates support assays, while nucleic-acid and nanoparticle conjugates extend the approach to biosensors, imaging, diagnostics, and research applications.
In ELISA, the enzyme component converts a supplied substrate into a colored or light-producing product. Measuring that output provides a signal linked to the assay’s molecular detection event, and enzymatic conversion can amplify the readout. Covalent attachment is useful here because it keeps the catalytic reporter associated with the selected detection molecule during the assay.
Beyond immunoassays, enzyme conjugates contribute to biosensors, molecular imaging, diagnostic tests, and targeted research tools. Their value comes from pairing an enzyme’s catalytic signal generation with a molecule or platform that contributes selectivity. This combination can improve sensitivity and specificity, making the conjugates useful when biological measurements must be both detectable and directed toward a chosen target.