FlAsH-EDT2 is a membrane-permeable fluorescent reagent that can label proteins. FlAsH-EDT2 can bind to CCXXCC motifs and nonspecific endogenous cysteine-rich proteins. FlAsH-EDT2 can only be used to label recombinant proteins that are expressed at very high levels.

Instructions
1. Prepare the marker:
1) Expression of recombinant protein: First, a recombinant protein containing the CCXXCC motif needs to be expressed (usually through molecular cloning technology). The motif is usually designed to interact with FlAsH-EDT2, usually in a specific region of the protein.
2) FlAsH-EDT2 reagent: FlAsH-EDT2 is provided as a chemical reagent. The fluorescent reagent can be diluted and prepared according to the instructions provided by the manufacturer. The concentration usually used is 1–10 μM.
2. Cell treatment:
1) In cells or tissues, FlAsH-EDT2 is added to the culture medium or buffer.
2) After entering the cell, the reagent will bind to the target protein containing a specific motif (such as CCXXCC) and form a fluorescent signal.
3) The fluorescent signal can be observed by fluorescence microscopy or flow cytometry.
3. Labeling time: Let FlAsH-EDT2 react with the target protein in the cell for a certain time (usually 15-30 minutes), then remove the unbound reagent by washing to reduce the background signal.
4. Observation and analysis: Use suitable fluorescence microscope equipment to observe the location and distribution of fluorescently labeled proteins; further cell co-localization experiments, protein interaction analysis, etc. can be performed.
Notes
1. High-level expression: FlAsH-EDT2 can only effectively label those recombinant proteins with very high expression levels in cells. For low-expressed proteins, the labeling effect may be poor.
2. Selective labeling: FlAsH-EDT2 binds to CCXXCC motifs and cysteine-rich endogenous proteins, so it is very important to ensure that the target protein contains these specific motifs and cysteine ​​residues.
3. Cytotoxicity: FlAsH-EDT2 may be slightly toxic to cells at certain concentrations, and attention should be paid to concentration and exposure time when using it.