Protease Catalyzed Labeling
Protease Catalyzed Labeling - Related Videos
09:43
Protease- and Acid-catalyzed Labeling Workflows Employing 18O-enriched Water
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Cited by 2 •
2013
Stable isotope labeling workflows employing 18O-enriched water (LeO-workflows) are versatile tools for quantitative and qualitative proteomics studies. In protease-assisted (PALeO) workflows, 18O-atoms are introduced by proteolytic cleavage and carboxyl oxygen exchange reactions mediated by proteases. In the acid-catalyzed (ALeO) workflow, 18O-atoms are introduced by carboxyl oxygen exchange at low pH.
09:00
Use of the Protease Fluorescent Detection Kit to Determine Protease Activity
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Cited by 15 •
2009
The Protease Fluorescent Detection Kit is designed for the measurement of protease activity using fluorometry. It is also suitable for detection of trace amounts of protease contamination. The method is based on the proteolytic hydroysis of a proprietary formulation of a FITC-labeled casein substrate.
06:19
Palladium-Catalyzed Cross Coupling
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2023
Source: Vy M. Dong and Faben Cruz, Department of Chemistry, University of California, Irvine, CA This experiment will demonstrate the concept of a palladium-catalyzed cross coupling. The set-up of a typical Pd-catalyzed cross coupling reaction will be illustrated. Pd-catalyzed cross coupling reactions have had a profound effect on how synthetic chemists create molecules. These reactions have enabled chemists to construct bonds in new and more efficient ways. Such reactions have found widespread...
11:37
Sigma's Non-specific Protease Activity Assay - Casein as a Substrate
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Cited by 414 •
2008
Proteases break peptide bonds. In the lab, it is often necessary to measure and/or compare the activity of proteases. Sigma's non-specific protease activity assay may be used as a standardized procedure to determine the activity of proteases.
02:24
Acid-Catalyzed Ring-Opening of Epoxides
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2023
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
FAQs
Selectivity begins with molecular recognition between the protease and a defined amino acid sequence on the target protein or peptide. This recognition positions the substrate so labeling occurs at a selected site rather than indiscriminately across the molecule. As a result, researchers can associate the detected signal with a particular protein region or processing event.
Protease-mediated cleavage and peptide-bond formation represent two distinct ways to place a label. Cleavage can expose or generate a labeled fragment, whereas bond formation directly links the label to the selected protein or peptide site. The choice affects how the labeled product is interpreted in studies of protein processing, identity, or localization.
The intended measurement guides label selection. Fluorescent tags support imaging and localization, while affinity tags enable selective recovery or purification; other detectable labels can help identify proteins in complex biological samples. Matching the tag to the readout allows the same site-specific chemistry to answer different questions about protein abundance, position, or interactions.
The method can connect a protein with its cellular location, interaction partners, processing state, or dynamic behavior. Because labeling is directed to a selected site, the resulting signal can provide more context than an undifferentiated protein stain. These capabilities support analysis in cells as well as in more complex biological samples.
In complex samples, site-directed tagging helps distinguish the selected protein or peptide from surrounding biological material. Researchers can then use fluorescence to visualize the labeled target or affinity-based handling to enrich it for analysis. This combination of molecular recognition and an interpretable tag improves the connection between a signal and its biological source.
Spatial control allows researchers to place detectable information at a chosen position on a protein rather than labeling without regard to site. That precision is useful when examining where proteins reside, how they interact, or how their processing changes within cells. The resulting measurements can preserve relationships between molecular events and cellular context.