Azido-PEG4-Ala-Ala-Asn(Trt)-PAB | CAS 2055042-67-4

Azido-PEG4-Ala-Ala-Asn(Trt)-PAB is a PEG-linked azide-bearing peptide–PAB scaffold designed for strain-promoted or copper-catalyzed azide click bioconjugation workflows. As an azide-functional reagent, it serves as a versatile handle for attaching peptide-based motifs to biomolecules, targeting ligands, or imaging reporters while maintaining aqueous solubility through the PEG spacer. The presence of the PAB (p-aminobenzyl) element and protected amino acid side chain enables downstream conjugate construction where peptide context and linker stability are important for research-grade molecular imaging, probe development, and materials functionalization.

1. Peptide Conjugate Building

Azido-PEG4-Ala-Ala-Asn(Trt)-PAB is commonly used as a click-compatible peptide building block to prepare conjugates for chemical biology studies, where a defined peptide sequence context is required alongside an azide functional group. Researchers incorporate this reagent into workflows that generate PEGylated peptide constructs for studying linker-dependent behavior, multivalent binding formats, and controlled presentation of peptide motifs on carriers such as proteins, polymers, or nanoparticles. The PEG4 spacer helps maintain solubility and reduces aggregation during labeling and purification, which is particularly valuable when assembling complex conjugates for analytical characterization.

2. Molecular Imaging Probe Labeling

Azido-PEG4-Ala-Ala-Asn(Trt)-PAB supports the preparation of imaging and detection reagents by enabling modular attachment of azide-bearing peptide scaffolds to fluorescent dyes, affinity tags, or other signal-generating reporters through click chemistry. In molecular imaging and diagnostic reagent development pipelines, this reagent is used to introduce a peptide-defined linkage environment that can influence probe architecture, steric accessibility, and conjugate stability in aqueous assay conditions. The azide handle makes it compatible with widely used click partners, allowing rapid exchange of the imaging moiety while keeping the peptide–PAB framework consistent across probe libraries.

3. Targeted Bioconjugation Platforms

Azido-PEG4-Ala-Ala-Asn(Trt)-PAB is frequently selected for targeted bioconjugation platform development where peptide-containing linkers must be appended to targeting ligands or scaffold proteins in a controlled and modular manner. Chemical biology groups use this reagent to generate conjugates that combine peptide structural elements with azide–click coupling to biomolecular vectors, enabling systematic variation of linker length, PEG spacing, and overall conjugate geometry. The resulting constructs are well suited for mechanistic studies of conjugate assembly, stability in labeling buffers, and performance in downstream analytical workflows such as gel-based characterization and chromatographic verification.

4. Functionalized Biomaterials Linkers

Azido-PEG4-Ala-Ala-Asn(Trt)-PAB is applied in biomaterials science to introduce peptide–PAB motifs onto polymer surfaces, hydrogel networks, or particulate supports via azide click coupling strategies. Materials researchers use this reagent to create functionalized surfaces and linkers that incorporate PEG-mediated hydrophilicity, improving compatibility with aqueous processing and enabling reproducible conjugation density during material fabrication. The peptide context offers an additional structural element for constructing responsive or addressable material interfaces, supporting tool development for assays, surface-based binding studies, and characterization of conjugate presentation on solid supports.