Transglutaminases (TGases) are enzymes that catalyze the formation of a stable isopeptide bond between the acyl group of the glutamine side chain and the alkyl amine of the lysine side chain. TGases are ubiquitous in multicellular organisms and play a role in protein cross-linking events in migration, apoptosis, and wound healing, as well as in physiological disorders such as Huntington’s disease and celiac sprue. In contrast to mammalian TGases, bacterial TGases do not require cofactors, such as Ca2+ or GTP, and function over a broad range of pH, buffers, and temperatures.
With its strict substrate specificity and remarkable activity, enzyme-promoted bioconjugation provides a viable alternative to conventional protein labeling methods. Enzymes can be easily isolated from cell culture, and are low-cost and environmentally friendly. Therefore, a variety of enzymes are used for site-specific protein modifications that are generally limited to the N- or C-terminus of the protein. TGases differ from these enzymes in that their targeted residues do not need to be terminally located. They allow labeling or modification at any accessible and reactive position on proteins. Therefore, TGases can be used as a labeling device for protein substrates whose termini are not amenable to modified or which require internal modification. Biotinylation, PEGylation, or fluorescent dye site-specific labeling of proteins (such as primary amines or peptides containing glutamine) are common applications of TGase labeling.
TGase mediated protein labeling requires accessible lysine residues or glutamine residues on the target protein surface and these substrate sequences are not generally abundant on proteins. If no lysine or glutamine residues are accessible, substrate sequence tags may be introduced recombinantly.
TGase Protein Labeling Kits are designed to easily obtain milligram amounts of labeled proteins. TGases catalyzed labeling requires accessible glutamine (Q) or lysine (K) residues on the surface of target proteins. In the first step, Substrate Finder Kit is used to determine whether the target protein contains accessible glutamine residues or lysine residues, or both, or none at all. In addition, Substrate Finder Kit indicates which of the following labeling kits is appropriate to modify the target protein with the desired label: biotin, PEG1088, PEG5000 or ATTO-488™, ATTO-532™, ATTO-550™, ATTO-647 N™, ATTO-700™.
Product Name | Applications | Label |
---|---|---|
Substrate Finder Kit | For determination of TGase substrate properties of proteins | |
Biotin TGase Protein Q-Labeling Kit | For labeling proteins containing accessible glutamine (Q) residues | Biotin |
PEG1,088 TGase Protein Q-Labeling Kit | PEG1088 | |
ATTO-488TM TGase Protein Q-Labeling Kit | ATTO-488™ | |
ATTO-532TM TGase Protein Q-Labeling Kit | ATTO-532™ | |
ATTO-550TM TGase Protein Q-Labeling Kit | ATTO-550™ | |
ATTO-647NTM TGase Protein Q-Labeling Kit | ATTO-647N™ | |
ATTO-700TM TGase Protein Q-Labeling Kit | ATTO-700™ | |
Biotin TGase Protein K-Labeling Kit | For labeling proteins containing accessible lysine (K) residues | Biotin |
PEG1,088 TGase Protein K-Labeling Kit | PEG1088 | |
PEG5,000 TGase Protein K-Labeling Kit | PEG5000 |
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