TR X NHS ester, 5-isomer is a sulfo analog of ROX dyes. It has similar spectral properties and emits in the red region of the spectrum. TR X is a dye with an aminocaproic acid linker that provides spacing between the fluorophore and the biomolecule.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.