TAMRA azide, 6-isomer is a xanthene dye with orange emission for covalent labeling of various types of biomolecules (excitation wavelength λ=312nm, emission wavelength λ=540nm) [1,2]. TAMRA azide, the 6-isomer, can be coupled with alkynylated histones and analyzed using fluorescence detection[2].
References:
[1] Kvach M V, Stepanova I A, Prokhorenko I A, et al. Practical synthesis of isomerically pure 5-and 6-carboxytetramethylrhodamines, useful dyes for DNA probes[J]. Bioconjugate chemistry, 2009, 20(8): 1673-1682.
[2] Willnow S, Martin M, Lüscher B, et al. A selenium‐based click AdoMet analogue for versatile substrate labeling with wild‐type protein methyltransferases[J]. ChemBioChem, 2012, 13(8): 1167-1173.