mFluor™ UV520 Maleimide is an excellent building block that can be readily used for labeling biomolecules that have a free thiol (SH) group such as antibodies and thiol-modified oligos. mFluor™ UV 520 dyes have fluorescence excitation and emission maxima of ~350 nm and ~520 nm respectively. These spectral characteristics make them a unique color for flow cytometry application. mFluor™ UV520 Maleimide is reasonably stable and shows good reactivity and selectivity with protein amino groups. mFluor™ UV520 Maleimide provides a convenient tool to label monoclonal, polyclonal antibodies or other proteins (>10 kDa) for flow cytometric applications with the UV laser excitation. mFluor™ UV dyes are optimized to be excited with a UV laser at 350 nm. AAT Bioquest offers the largest collection of fluorescent dyes that are excited by UV laser at 350 nm. mFluor™ dyes are developed for multicolor flow cytometry-focused applications. These dyes have large Stokes Shifts, and can be well excited by the laser lines of flow cytometers (e.g., 350 nm, 405 nm, 488 nm and 633 nm).