Parameters

Appearance: Yellow solid soluble in water 
Ex/Em (with DNA): 352/461 nm

Ex/Em (no DNA): 346/460 nm

Molecular Formula: C₂₅H₂₄N₆O • 3HCl
Molecular Weight: 533.88

Storage

Store at -20°C and protect from light. When stored as directed, product is stable for at least 6 months.

Description

Hoechst 33258 is a cell membrane-permeant, minor groove -binding blue fluorescent DNA stains. The dye is weakly fluorescent in solution, but the fluorescence becomes bright after binding to DNA in the small grooves in the AT-rich region. The dye is widely used in cell cycle and apoptosis studies as nuclear counterstains. Hoechst 33258 is slightly more water soluble than Hoechst 33342. The dyes can be used to stain live or fixed cells with no wash step required.

Hoechst can also be used to stain live bacteria (gram-positive and gram-negative), but in live yeast the staining is weak and not nuclear. 

Notes

1. Hoechst dye is usually used to stain mammalian cells. It can also stain bacteria. It is recommended to stain with a final concentration of 12-15 μg / mL in PBS or 150 mM NaCl for 30 min at room temperature. Staining of yeast is weaker. Dead cells are usually stained more brightly than live cells.

2. The solubility of Hoechst 33258 can reach 10 mg/mL when dissolved in water. When staining nucleus, the working concentration of Hoechst 33258 is 0.5-10 μg/mL. You may need to optimize the staining procedure for each particular cell type by varying the dye concentration.