Tetrazine-Ph-NHS ester | CAS 1616668-55-3

Tetrazine-Ph-NHS ester is a bifunctional click chemistry reagent that combines a strained tetrazine moiety with an N-hydroxysuccinimide (NHS) ester for efficient coupling to primary amines. As a key component of tetrazine-based inverse electron-demand Diels–Alder (IEDDA) click chemistry, it is widely used to introduce tetrazine handles onto proteins, peptides, and other amine-containing biomolecules prior to rapid bioorthogonal conjugation. The aryl spacer (Ph) helps maintain accessibility of the tetrazine for downstream labeling workflows commonly used in chemical biology, molecular imaging reagent development, and biomaterials functionalization.

1. Protein Labeling Workflows

Tetrazine-Ph-NHS ester is used to functionalize amine-rich proteins and protein conjugates with tetrazine groups, enabling subsequent click coupling to complementary trans-cyclooctene or strained alkene partners in labeling workflows. Researchers and core facilities frequently apply this strategy to prepare imaging probes, affinity reagents, and multivalent protein constructs where controlled installation of the tetrazine handle is required for efficient downstream assembly. The NHS ester reactivity supports straightforward conjugation to lysine residues under standard bioconjugation conditions, while the tetrazine functionality provides the bioorthogonal “click” handle for modular post-conjugation steps.

2. Antibody and Ligand Conjugation

Tetrazine-Ph-NHS ester supports preparation of tetrazine-bearing antibodies, antibody fragments, and targeting ligands by reacting with accessible primary amines during bioconjugation. This approach is commonly selected in molecular imaging and diagnostic reagent development pipelines because it allows modular construction of antibody–probe or antibody–material hybrids through a subsequent tetrazine click step. By installing tetrazine groups on the targeting scaffold first, teams can later couple to imaging reporters, polymeric carriers, or detection tags using standardized complementary partners, improving workflow flexibility for probe libraries and reagent optimization studies.

3. Peptide and Small Biomolecule Tagging

Tetrazine-Ph-NHS ester is well suited for introducing tetrazine handles onto peptides and other amine-containing biomolecules used as targeting motifs, binding reagents, or biochemical tools. In chemical biology applications, the resulting tetrazine-functionalized peptides can be used as modular building blocks for assembling fluorescent or affinity-tagged constructs via tetrazine click chemistry. The NHS ester functionality is particularly relevant when a convenient, general method for amine coupling is needed to generate consistent tetrazine-labeled reagents for downstream assays, imaging experiments, and structure–function studies.

4. Biomaterials Surface Functionalization

Tetrazine-Ph-NHS ester is applied to functionalize biomaterial surfaces and polymeric materials that present primary amines, including amine-activated coatings and amine-containing hydrogels used in research-grade materials platforms. By covalently attaching tetrazine moieties to the material interface, the reagent enables subsequent spatially and temporally controlled conjugation of complementary click partners for building multilayer coatings, immobilized probe arrays, and modular biointerfaces. This surface-first strategy is frequently used in biomaterials science to create stable, reactive materials that can be further decorated under mild conditions, supporting the development of advanced assay surfaces and engineered chemical biology tools.