Psoralen-PEG3-Biotin

1. Prepare a Psolaren-PEG3-Biotin stock solution by adding 70 μL (for Cat# 39050) or 350 μL (for Cat# 39051) of DMSO to the vial of Psolaren-PEG3-Biotin. 

   Note: Any unused stock solution should be divided into single-use aliquots and stored at ≤-20 °C after preparation. Protect from light and avoid repeated freeze-thaw cycles.

The following protocol is to be used as a general guideline and may require optimization for your specific application and experimental system.

1. Adjust DNA or RNA to the desired concentration (e.g., 20-100 μg/mL) in TE buffer (10 mM Tris, 1 mM EDTA, pH 7.4).

   Note: To improve the binding of dye to nucleic acid, DNA can be denatured by boiling for 5 minutes. After boiling, the DNA tube should be quickly cooled by placing it in a dry ice/ethanol bath.

2. Add 1 μL of Psolaren-PEG3-Biotin stock solution to the DNA or RNA (100 μL volume) and mix well.

   Note: A serial dilution of the Psolaren-PEG3-Biotin stock solution may be required when using small reaction volumes.

3. Irradiate the tube from above using a long wavelength UV light source for at least 20-30 minutes.

4. To remove any non-reacted Psolaren-PEG3-Biotin, precipitate the sample with 0.5 M NaCl and two volumes of 100% ethanol at -20 °C for a minimum of 30 minutes. After centrifugation, wash the pellet with 70% ethanol and allow it to dry. Dissolve the biotinylated sample in water or a buffer of your choice.

5. Biotinylated DNA can then be verified using HABA and gel electrophoresis.