5(6)-TMARA C2 maleimide

Although tetramethylrhodamine (TMR) maleimides and iodoacetamides are popular thiol-reactive labeling reagents, they are quite unstable in water, and the commercial tetramethylrhodamine maleimides and iodoacetamides often have lower purities than other tetramethylrhodamine labeling reagents (such as TAMRA SE reagents) due to their synthetic difficulties. In addition, the labeling efficiency of tetramethylrhodamine maleimides and iodoacetamides is often lower compared to that of other tetramethylrhodamine labeling dyes. TMR C2 maleimides are proven to be superior replacements to tetramethylrhodamine maleimides and iodoacetamides. These reagents react with thiol compounds, such as amino acids, peptides and proteins, to give bright red fluorescent conjugates that are extremely stable. Compared to tetramethylrhodamine maleimides and iodoacetamides, TMR C2 maleimides have higher labeling efficiency, and more importantly, the resulting conjugate is often more fluorescent than the corresponding Texas Red conjugate. The conjugates of TMR C2 maleimides have the identical excitation and emission wavelengths at 544/572 nm to those of tetramethylrhodamine maleimides or iodoacetamide.