PMA™ (propidium monoazide) is a high affinity photoreactive DNA binding dye invented by scientists at Biotium. The dye is weakly fluorescent by itself but becomes more fluorescent after binding to nucleic acids. It preferentially binds to dsDNA with high affinity. Upon photolysis, the photoreactive azido group on the dye is converted to a highly reactive nitrene radical, which readily reacts with any hydrocarbon moiety at the binding site to form a stable covalent nitrogen-carbon bond, thus resulting in permanent DNA modification. The dye is nearly completely cell membrane-impermeable, and thus can be selectively used to modify only exposed DNA from dead cells while leaving DNA from viable cells intact. This feature makes the dye highly useful in the selective detection of viable pathogenic cells by quantitative real-time PCR in the presence dead cells whose DNA has been PMA-modified and thus can not be amplified. Since Biotium first developed PMA dye, there have been numerous publications on the use of the dye in pathogenic bacterial detection related to food and water safety, medical diagnosis and biodefense; download the PMA Reference List. Please also see PMA dye in H2O (40019), a convenient ready-to-use format.
For photoactivation of PMA 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.
- Molecular weight: 511
- Abs = 464 nm (before photolysis)
- Abs/Em = 510/610 nm (following photolysis and covalent attachment to DNA/RNA)
- Dark red solid soluble in DMSO or DMF
- Store at 4°C and protect from light at all times