Ethidium monoazide bromide (EMA) DNA/RNA binding dye
Supplier: Biotium
Ethidium monoazide bromide (EMA) is a fluorescent nucleic acid stain with a photoaffinity label. The dye, after photolysis, binds covalently to nucleic acids. The dye has been used to footprint drug binding sites on DNA, to modify plasmid DNA, and for labeling yeast cells for leukocyte phagocytosis assays.
- Ex (pH 3) = 458 nm
- λEx/λEm (after photocrosslinking to nucleic acid) = 510/600 nm
- Orange solid soluble in DMF, or ethanol
- Store desiccated at 4°C or -20°C and protect from light, especially in solution
A particularly useful application of the dye is to label dead cells in a mixed population of live and dead cells. Because EMA is relatively impermeant to live cells, it selectively binds DNA in dead cells. Photolysis renders the dead cell DNA covalently labeled with the dye. One can then wash and fix the cell preparation for analysis by microscopy, fluorescence plate reader or flow cytometry. The major advantage of this method is that researchers can avoid extensive manipulation of live pathogenic organisms.
EMA has been used to differentiate between viable and dead bacteria by 5′-nuclease PCR.
or viability PCR applications, Biotium also offers propidium monoazide iodide (PMA, catalog numbers 40013 and 40019) as well as our new and improved viability PCR dye, PMAxx™ (catalog number 40069). PMA and PMAxx™ are less membrane permeant than EMA and therefore more selective for dead cell labeling for qPCR quantitation of viable bacteria.
For photoactivation of PMA, PMAxx™ or EMA dye, we recommend the use of Biotium’s PMA-Lite™ LED Photolysis Device (E90002), which is designed to conduct photolysis under controlled conditions.
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Formula:
C₂₁H₁₈BrN₅ MW: 420.305 g/mol Storage Temperature: Refrigerator |
CAS Number:
58880-05-0 |
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