3D model (JSmol)
|Molar mass||1270.43 g/mol|
|Appearance||Red to dark purple powder|
|R-phrases (outdated)||R26/27/28 R36/37/38|
|S-phrases (outdated)||S26 S28 S36/37 S45|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
7-Aminoactinomycin D (7-AAD) is a fluorescent chemical compound with a strong affinity for DNA. It is used as a fluorescent marker for DNA in fluorescence microscopy and flow cytometry. It intercalates in double-stranded DNA, with a high affinity for GC-rich regions, making it useful for chromosome banding studies.
With an absorption maximum at 546 nm, 7-AAD is efficiently excited using a 543 nm helium–neon laser; it can also be excited with somewhat lower efficiency using a 488 nm or 514 nm argon laser lines. Its emission has a very large Stokes shift with a maximum in the deep red: 647 nm. 7-AAD is therefore compatible with most blue and green fluorophores – and even many red fluorophores – in multicolour applications.
7-AAD does not readily pass through intact cell membranes; if it is to be used as a stain for imaging DNA fluorescence, the cell membrane must be permeabilized or disrupted. This method can be used in combination with formaldehyde fixation of samples.
7-AAD is also used as a cell viability stain. Cells with compromised membranes will stain with 7-AAD, while live cells with intact cell membranes will remain dark.
The related compound actinomycin D is nonfluorescent, but binds DNA in the same way as 7-AAD. Its absorbance changes when bound to DNA, and it can be used as a stain in conventional transmission microscopy.
- 7-Aminoactinomycin D at Interchim
- Liu X; Chen H; Patel D (1991). "Solution structure of actinomycin-DNA complexes: drug intercalation at isolated G-C sites". J Biomol NMR. 1 (4): 323–47. doi:10.1007/BF02192858. PMID 1841703.
- Latt S (1977). "Fluorescent probes of chromosome structure and replication". Can J Genet Cytol. 19 (4): 603–23. PMID 76502.