NBD-TMA (trimethylammonium) is a small (139
u), positively charged (+1) fluorescent dye. It was also known as
EAM-1 (N,N,N,-Trimethyl-2ethanaminium
iodide) when it was briefly supplied by
Macrocyclics Company as an iodide complex.
NBD-TMA has an excitation maximum at 458
nm and an emission maximum at 530 nm. It also has a smaller local excitation maximum around 343 nm. The
molar extinction coefficient is about 13,000 cm<sup>-1</sup>M<sup>-1</sup> and its overall effective fluorescence is about 1% that of
fluorescein. It is only mildly sensitive to
halide ion collision quenching.
NBD-TMA was designed as a probe for monitoring
renal transport of organic
cation. As a small, positively charged
fluorophore, it has also seen use as a tracer for measuring
gap junction coupling in cases of cation selective
connexin channels.
Further reading
- PMID 10864014
- PMID 15869481
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