SR101-PEO12 SE (Sulforhodamine 101-PEO12-propionic acid succinimydyl ester; Texas Red®-PEO12 SE) has an approximately 47 Angstrom water-soluble PEG spacer that separates the dye from the amine-reactive SE group. &lamba;Ex/&lamba; Em= 583/603nm Dark purple solid soluble in DMF or DMSO Store at -20°C and protect from light, especially in solution C62H86N4O22S2 MW: 1303.49   Texas Red is a registered trademark of Thermo Fisher Scientific.