PEG

Methyltetrazine-PEG4-STP Ester is an amine-reactive, water-soluble labeling reagent used to modify proteins, antibodies, and other amine-containing biopolymers in aqueous media. Methyltetrazine-PEG4-STP Ester undergoes hydrolysis in aqueous media at much slower rate compared to Methyltetrazine-Sulfo NHS Ester allowing for more efficient labeling of biomolecules in aqueous media.

Sulfo DBCO-TFP Ester is a water-soluble, amine-reactive labeling reagent that enables simple and efficient incorporation of Sulfo DBCO moiety onto amine-containing molecules. The hydrophilic, sulfonated spacer arm greatly improves water solubility of DBCO derivatized molecules, in many cases making them completely soluble in aqueous media. A short spacer arm adds minimal mass to modified molecules.

Biotin-PEG4-STP Ester (4-Sulfo-2,3,5,6-tetrafluorophenyl ester) is an amine-reactive, water-soluble labeling reagent used to modify proteins, antibodies, and other amine-containing biopolymers in 100% aqueous media. The hydrophilic polyethylene glycol (PEG) spacer arm of this reagent imparts water solubility that is transferred to the labeled molecule, thus reducing aggregation of labeled proteins stored in solution. The PEG spacer arm also gives the reagent a long and flexible connection to minimize steric hindrance involved with binding to avidin molecules.

Alkyne Sphinganine a metabolic labeling reagent that contains a terminal alkyne moiety that allows for the subsequent tagging of protein−lipid complexes by click chemistry. The terminal alkyne group can be used in a highly specific linking reaction with azide-containing reagents, known as ‘click chemistry’, in the presence of a copper (Cu)-containing catalyst allowing for the visualization and proteomic profiling of protein−sphingolipid complexes in living cells.

Metabolic labeling with unnatural sugar substrates is a powerful alternative for investigating glycoconjugates in living organisms. Trehalose glycolipids can be metabolically labeled with 6-azide-modified trehalose (TreAz) analogues in live mycobacteria, enabling bioorthogonal ligation with alkyne-functionalized fluorescent probes. This strategy can be used for imaging glycolipid distribution, trafficking, and dynamics as well as metabolite profiling and discovery.

Metabolic labeling with unnatural sugar substrates is a powerful alternative for investigating glycoconjugates in living organisms. Trehalose glycolipids can be metabolically labeled with O-Alkyne-Trehalose (O-AlkTMM) analogues in live mycobacteria, enabling bioorthogonal ligation with azide-functionalized fluorescent probes. This strategy can be used for imaging glycolipid distribution, trafficking, and dynamics as well as metabolite profiling and discovery.

Disulfide Biotin alkyne is an azide-activated cleavable biotin probe that allows for efficient recovery of avidin-bound protein complexes in affinity-based assays. This reagent contains a biotin moiety linked to an alkyne group through a spacer arm containing a cleavable disulfide linker. Under reducing conditions (50 mM dithiothreitol, 10 mM 2-mercaptoethanol or 1% sodium borohydride), the disulfide bonds are cleaved, releasing the biotin tag and any avidin conjugate bound to it.

Mono-sulfone is a thiol-specific labeling reagent that undergo alkylation to generate a thio-ether bond between the protein and mono-sulfone activated reagent. Once mono-sulfone reagent is conjugated to a protein or peptide, exchange reactions leading to deconjugation can be easily avoided by treating the conjugate with a mild reducing agent in a way analogous to the process used for conjugation reactions involving reductive amination.

Water-soluble, substrate for sortase mediated labeling of proteins. Sortase catalyzes a transpeptidase reaction between a specific internal sequence of a protein and an amine group present on the N-terminus of triglycine recently has become an area of great interest. This method of labeling proteins has been denoted as “Sortagging”. Proteins conjugated to DBCO-Gly-Gly-Gly can be further modified with azide-containing molecules creating site-specific protein conjugates. Examples of creating protein conjugates using sortagging include site-specifically PEGylating proteins,1 site-specific protein-lipid conjugates,2 and constructing peptides and glycosylphosphatidylinositol chimeras.3 Sortase has also been used in peptide synthesis to cyclize peptides to create macrocyclic peptides, glycopeptides4 and protein−protein conjugates.5