FlAsH-EDT2 is a pro-fluorescent, membrane-permeable biarsenical compound that binds covalently to a tetracysteine sequence (CCPGCC), which is engineered into target proteins.[1],[2] It binds proteins that have the CCPGCC tag almost immediately after translation.[2] FlAsH-EDT2 is commonly used to study protein trafficking, folding, and interactions in living cells or cell lysates.[2],[3],[4] This green-emitting fluorophore is excited at 508 nm, with emission at 528 nm.[4]

Reference:
[1]. Griffin, B.A., Adams, S.R., and Tsien, R.Y. Specific covalent labeling of recombinant protein molecules inside live cells. Science 287(5374), 269-272 (1998).
[2]. Rudner, L., Nydegger, S., Coren.L.V., et al. Dynamic fluorescent imaging of human immunodeficiency virus type 1 gag in live cells by biarsenical labeling. J.Virol. 79(7), 4055-4065 (2005).
[3]. Luedtke, N.W., Dexter, R.J., Fried, D.B., et al. Surveying polypeptide and protein domain conformation and association with FlAsH and ReAsH. Nat.Chem.Biol. 3(12), 779-784 (2007).
[4]. Perdios, L., Bunney.T.D., Warren, S.C., et al. Time-resolved FRET reports FGFR1 dimerization and formation of a complex with its effector PLCγ1. Adv.Biol.Regul. 60, 6-13 (2016).