TMRM +

Structural formula
General
Surname	Tetramethylrhodamine methyl ester (perchlorate)
other names	TMRM +
Molecular formula	C 25 H 25 ClN 2 O 7
Brief description	green solid
External identifiers / databases
CAS number 115532-50-8 EC number 634-218-8 ECHA InfoCard 100.162.219 Wikidata Q2384557
properties
Molar mass	500.93 g mol −1
Physical state	firmly
solubility	soluble in methanol and DMSO
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Tetramethylrhodamine-methylester ( TMRM ⁺ ) is a rhodamine - fluorescent dye , which for the first time in 1988 by Ehrenberg et al. was synthesized.

TMRM ⁺ is not cytotoxic and is therefore used in life cell imaging to track temporary changes in the membrane potential of the mitochondria . Due to its positive charge, TMRM ⁺ accumulates in the negatively charged mitochondria. When the mitochondria are depolarized (e.g. at the beginning of apoptosis ), stored anions are released there, whereupon the TMRM ⁺ concentration also drops there.

Both the cell membrane and the mitochondrial membrane are permeable to TMRM ⁺ in both directions . The dye does not bind in cells, but only accumulates in anionic areas due to its concentration gradient. It can therefore also be completely washed out with buffers that do not contain TMRM ⁺ .

TMRM ⁺ has two absorption maxima at λ _max = 515 nm and 555 nm and emits at λ _max = 575 nm. Quenching effects can occur at concentrations above 50 nM .

The abbreviation TMRM is often used instead of TMRM ⁺ , although this is also used for tetramethylrhodamine maleimide , which can lead to confusion.

Individual evidence

1. ↑ ^{a b c} data sheet Tetramethylrhodamine methyl ester perchlorate from Sigma-Aldrich , accessed on May 9, 2017 ( PDF ).
2. ↑ Invitrogen data sheet  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (T668)  
3. ↑ Ehrenberg, B. et al. (1988): Membrane potential can be determined in individual cells from the nernstian distribution of cationic dyes. In: Biophys J. Vol. 53, No. 5, pp. 785-94. PMID 3390520
4. ↑ ^{a b} Farkas, DL et al. (1990): Simultaneous imaging of cell and mitochondrial membrane potentials. In: Biophys J. Vol. 57, No. 3, pp. 684-700. PMID 2611324
5. ↑ Floryk D. & Houstĕk J. (1999): Tetramethyl rhodamine methyl ester (TMRM) is suitable for cytofluorometric measurements of mitochondrial membrane potential in cells treated with digitonin . In: Bioscience Reports. Vol. 19, No. 1, pp. 27-34. PMID 10379904
6. ↑ Nicholls, DG (2006): Simultaneous monitoring of ionophore- and inhibitor-mediated plasma and mitochondrial membrane potential changes in cultured neurons. In: J Biol Chem Vol. 281, No. 21, pp. 14864-14874. PMID 16551630
7. ↑ Ward et al. (2000): Mitochondrial Membrane Potential and Glutamate Excitotoxicity in Cultured Cerebellar Granule Cells. In: J Neurosci Vol. 20, No. 19, pp. 7208-7219. PMID 11007877