ROX is a bright rhodamine dye with emission maximum around 580 nm. It is widely used for the labeling of biomolecules. As other rhodamine dyes, it comes as two isomers, 5-ROX and 6-ROX. Although these isomers have almost identical spectral properties, they need to be separated to avoid doubling of labeled products on HPLC or electrophoresis.
This derivative contains thiol-reactive maleimide moiety for the attachment of ROX fluorophore to SH groups, such as cystein residues in proteins and peptides.