SiR-tetrazine is a clickable derivative of SiR. This probe reacts with dienophiles such as trans-cyclooctene (TCO) or bicyclononyne (BCN) derivatives, enabling the preparation of custom SiR probes and conjugates. SiR-tetrazine is particularly useful in combination with unnatural amino acid (UAA) incorporation to prepare site selective protein conjugates. SiR-tetrazine is cell permeable and fluorogenic, it can be used to stain live cells as well as fixed ones. SiR is compatible with GFP and/or m-cherry fluorescent proteins. It can be imaged with a standard Cy5 filterset.
λabs 652 nm
εmax 1.0·105 mol-1·cm-1
λfl 674 nm
MW =641.8 g/mol
CF260 = 0.116
CF280 = 0.147
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