Photoactivatable fluorescent dye; supplied as an NHS ester for coupling to primary amine groups. Non-fluorescent until activated at 365 nm. Compatible with self-labeling tag systems (e.g. HaloTag? and SNAPtag? ). Suitable for single molecule tracking and super resolution microscopy in live cells, specifically live cell sptPALM and fixed cell PALM. Can be multiplexed with PA Janelia Fluor? 549, SE (Cat. No. 6149) to perform two-colour sptPALM in live cells with activation at 405nm. Cell permeable. Excitation maximum = 649 - 651 nm; emission maximum = 663 - 665 nm. Upon protein conjugation the efficiencies of photoconversion improve substantially. Low background staining. HaloTag is a trademark of Promega Corporation, and SNAP-tag is a trademark of New England BioLabs, Inc.. MW (observed): 617.74.