7-aminoactinomycin

Structural formula
General
Surname	7-aminoactinomycin
other names	7-AAD
Molecular formula	C 62 H 87 N 13 O 16
External identifiers / databases
CAS number 7240-37-1 EC number 635-285-6 ECHA InfoCard 100.163.188 PubChem 14924508 ChemSpider 21326185 Wikidata Q259277
properties
Molar mass	1270.43 g mol −1
Physical state	firmly
solubility	1 mg / ml in chloroform
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 300 P: 301 + 330 + 331-310
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

7-Aminoactinomycin is an organic compound belonging to the class of peptides . It is mostly abbreviated as 7-AAD.

construction

Like all actinomycins , the actinoyl chromophore has a doubly methylated 2-aminophenoxazin-3-one system that is linked to pentapeptide lactone rings via two amide bonds. The basic structure of the chromopeptide 7-AAD is actinomycin D , which lacks the additional functional group of the 7-AAD, an amino group, at position 7.

Structure of actinomycin (for R = H) and 7-AAD (for R = NH ₂ )

properties

7-Aminoactinomycin is an orange-red solid in its pure form. It is soluble in dimethylformamide , dimethyl sulfoxide and chloroform .
In principle, 7-AAD has the same properties as the parent compound, actinomycin D, but, in contrast to this, it is not used as a cytostatic . The ability of the 7-AAD to intercalate the DNA is exploited by using it as a cell pigment . 7-AAD specifically intercalates between cytosine and guanine and changes its fluorescence properties. A special feature of 7-AAD is that, as with propidium iodide , only the DNA of non-viable cells is stained, as it can only penetrate cells without an intact cell membrane. 7-AAD is therefore also referred to as an avital dye .

This property is used in an apoptosis assay that examines the apoptosis (programmed cell death) of cells. During apoptosis, the asymmetrical structure of the cell membrane is lost . The phosphatidylserine (PS) localized in vital cells on the inside (the cytoplasmic side) of the membrane then also occurs increasingly in the outward-facing membrane side. In an assay to determine the stage of apoptosis, Doppler staining of the cells is carried out with a phosphatidylserine-specific dye, the protein Annexin V and with 7-AAD. Intact cells react negatively to both staining, early apoptotic cells react positively to PS staining, but negative to those with 7-AAD, late apoptotic (dead) cells react positively to both staining. Even completely necrotic cells react positively to staining with 7-AAD and annexin V.

The examinations themselves are carried out in a fluorescence microscope or in a flow cytometer . In both methods, the fluorescence is excited by a laser (usually 488 nm). The emission maximum is at 647 nm.

Absorption and fluorescence emission spectrum of 7-AAD bound to DNA

Others

According to the IUPAC nomenclature recommendations , the compound is called 2,7-diamino-4,6-dimethyl-3-oxo-N, N'-bis (7,11,14-trimethyl-2,5,9,12,15-pentaoxo -3,10-dipropan-2-yl-8-oxa-1,4,11,14-tetrazabicyclo [14.3.0] nonadec-6-yl) phenoxazine-1,9-dicarboxamide

Individual evidence

1. ↑ ^{a b c} data sheet 7-Aminoactinomycin D from Sigma-Aldrich , accessed on November 4, 2016 ( PDF ).

literature

• Schutte et al .: Annexin V binding assay as a tool to measure apoptosis in differentiated neuronal cells. In: J. Neurosci. Methods , 1998, 86, pp. 63-69.
• RM Wadkins, TM Jovin: Actinomycin D and 7-aminoactinomycin D binding to single-stranded DNA. In: Biochemistry , 1991, 30 (39), pp. 9469-9478.