QW-003
| Cat. No. | QW-003 |
| Categories | Fluorogenic Substrate |
| Molecular Weight | 8,544.75 Da |
| Specifications | 1mg / 5mg / Custom |
| Purity | ≥95% (RP-HPLC) |
| Storage | -80°C protected from light |
| Batch No. | Spec | Stock Qty | Grade | Status | COA |
|---|---|---|---|---|---|
| PA-2026-01 | 1mg | 20 | ≥95% | Available | - |
Ub-PA (Ubiquitin Activity-Based Probe) is a chemical probe tool designed on the ubiquitin scaffold. Its C-terminus carries an electrophilic warhead (Propargylamide, PA) that specifically and irreversibly reacts with the catalytic cysteine residue in the active site of DUB enzymes, enabling a streamlined "capture-label-identify" workflow. Unlike fluorogenic substrates, Ub-PA is not a substrate for activity detection — it is a probe tool for covalently labeling and enriching DUB proteins themselves.
Ub-PA mimics the natural C-terminal structure of ubiquitin and is recognized and bound by DUB enzymes at their active site. The electrophilic warhead (Propargylamide) then undergoes nucleophilic addition with the catalytic cysteine thiol group, forming a stable covalent thioether bond that irreversibly labels the active form of the DUB. The labeled DUB-probe complex can be detected by SDS-PAGE / Western Blot or enriched via biotin/fluorophore tags for MS-based identification.
Recommended probe concentration: 1–5 μM. Labeling conditions: 37°C, 30–60 min. Avoid free-thiol reducing agents (e.g., β-ME) in lysis buffer; use TCEP instead. Labeled samples can be separated by SDS-PAGE and detected using anti-ubiquitin antibody (e.g., FK2) or streptavidin-HRP after Click Chemistry biotinylation.
