Biotin-PEG4-methyltetrazine | CAS 1835759-81-3

Biotin-PEG4-methyltetrazine is a biotinylated, PEG4-linked methyltetrazine click chemistry reagent designed for fast inverse-electron-demand Diels–Alder (IEDDA) ligation with trans-cyclooctene (TCO) functional groups. The combination of a hydrophilic PEG spacer and a tetrazine warhead makes it well suited for aqueous labeling workflows where modular conjugation and affinity capture are required. Its biotin handle enables downstream enrichment, immobilization, and detection in biochemical assays, proteomics sample preparation, and imaging tool development.

1. Biotin Affinity Labeling

Biotin-PEG4-methyltetrazine is widely used as an affinity-tagging reagent to introduce biotin onto TCO-functionalized biomolecules, nanoparticles, or polymeric constructs in solution. Researchers rely on the PEG4 spacer to reduce steric effects during labeling and to improve accessibility of the biotin moiety for streptavidin-based workflows. This application is common in pull-down experiments, comparative labeling of binding partners, and preparation of biotinylated reagents for subsequent capture on streptavidin-coated surfaces or beads.

2. Proteomics Sample Preparation

Biotin-PEG4-methyltetrazine supports enrichment-based proteomics workflows where selective labeling of TCO-bearing targets is followed by streptavidin affinity isolation. In practice, the reagent is used to generate biotin-tagged conjugates that are compatible with downstream washing and fractionation steps, helping researchers reduce background and concentrate labeled species prior to LC-MS analysis or immunoblotting. The PEG4 linker contributes to robust handling in complex lysate environments by improving conjugate solubility and maintaining biotin accessibility during enrichment.

3. Cell Surface Reagent Conjugation

Biotin-PEG4-methyltetrazine is frequently employed in chemical biology workflows to label TCO-functionalized cell-surface or membrane-associated components with a biotin handle for downstream detection or sorting. The reagent’s aqueous compatibility and tetrazine-based click reactivity make it a practical choice for modular conjugation strategies that integrate affinity readouts. Typical use cases include preparing biotinylated probes for microscopy workflows, flow-based enrichment of labeled populations, and surface mapping of conjugated biomaterials in research settings.

4. Molecular Imaging Probe Building

Biotin-PEG4-methyltetrazine is used as a building block for constructing imaging and detection reagents that incorporate both a clickable tetrazine and a biotin affinity handle. Teams developing molecular imaging toolkits often use it to attach biotin to TCO-functionalized reporter scaffolds, enabling subsequent coupling to streptavidin/avidin systems, imaging platforms, or assay-compatible capture formats. The PEG4 spacer helps preserve probe performance by limiting nonspecific interactions and maintaining accessibility of the biotin for consistent signal generation in assay workflows.