5(6)-TAMRA PEG3 alkyne

The water soluble 5(6)-TAMRA PEG3 alkyne has a long PEG3 spacer that separates the dye tetramethylrhodamine (commonly known as TMR or TAMRA) from the terminal acetylene group. The water-soluble PEG3 spacer should minimize the interaction between the dye and the biomolecule to be labeled. With excitation maximum at 547 nm, the acetylene – TMR conjugate is an excellent match to the intense 546 nm spectral line of the mercury-arc laps used in most ?uorescence microscopes. This probe is also ef?ciently excited by the 543 nm spectral line of the Ar - Kr mixed gas laser commonly used in many confocal laser-scanning microscopes. The ?uorescence of the acetylene – tetramethylrhodamine conjugate as well as of many other rhodamine based probes is pH insensitive between 4 and 9, and exhibits excellent photostability.