Azido-PEG3-Val-Cit-PAB-OH | CAS 2055024-65-0

Azido-PEG3-Val-Cit-PAB-OH is a PEG-based azide-containing click chemistry building block designed for bioorthogonal conjugation workflows. It incorporates a Val-Cit motif and a PAB (p-aminobenzyl) trigger element commonly used in self-immolative or cleavage-responsive linker architectures, making it relevant for constructing modular, stimulus-sensitive conjugates. As an azide handle, it is typically paired with complementary cyclooctyne or strained-alkyne partners to enable efficient attachment to biomolecules, targeting ligands, or imaging scaffolds in molecular imaging, chemical biology, and materials research.

1. Cleavable Linker Conjugates

Azido-PEG3-Val-Cit-PAB-OH is widely used as a cleavable linker component in research-grade conjugate design, where downstream constructs benefit from a defined structural response element embedded within a PEG spacer. Teams in chemical biology and medicinal chemistry often incorporate this type of Val-Cit/PAB architecture to create modular platforms that can be assembled onto proteins, peptides, or small-molecule scaffolds via azide click chemistry. The PEG3 segment supports aqueous handling and reduces steric constraints during conjugation and subsequent assay workflows, while the azide functionality enables straightforward installation onto alkyne-functional partners for library generation and comparative studies.

2. Targeting Ligand Labeling

Azido-PEG3-Val-Cit-PAB-OH serves as a practical azide reagent for installing linker payloads onto alkyne-functional targeting ligands, including peptide-based binders and small-molecule recognition elements used in probe development. Researchers use this reagent to generate conjugation-ready intermediates that maintain solubility and spacing between the targeting moiety and the responsive trigger region. In molecular imaging and diagnostic reagent development pipelines, azide click handles are favored for rapid, orthogonal coupling strategies that support parallel synthesis of multiple labeled constructs with consistent linker geometry.

3. Molecular Imaging Probes

Azido-PEG3-Val-Cit-PAB-OH is commonly incorporated into probe scaffolds where a PEG spacer and a cleavage-responsive trigger element are desired to tune probe architecture for imaging reagent development. By providing an azide group for click conjugation, it enables attachment of the linker to cyclooctyne/strained-alkyne-bearing reporters, such as fluorophore or imaging-chelator conjugates, used in chemical biology toolsets. Molecular imaging groups frequently select PEG-based azide linkers to improve aqueous compatibility and to standardize conjugate spacing, supporting reproducible labeling across probe series.

4. Diagnostic Reagent Platforms

Azido-PEG3-Val-Cit-PAB-OH is used to build diagnostic reagent components that require modular, click-assembled linkers with defined spacing and a responsive element for downstream signal-generation concepts. Diagnostic reagent developers often rely on azide/strained-alkyne conjugation to rapidly couple linker payloads to detection handles, including alkyne-functional affinity reagents or assay-compatible reporter constructs. The Val-Cit/PAB motif integrated into the linker design supports the creation of structured conjugate architectures used in assay development workflows, where consistent linker identity and geometry are important for comparative evaluation of reagent formats.