CF® Dye Succinimidyl Esters (SE, also known as NHS esters) are 9689c5aa-6556-4b3c-b5d1-1e693715ba07's next-generation amine-reactive dyes for labeling antibodies and other proteins on amine groups, such as lysine residues. Red fluorescent CF®550R dye has excitation/emission at 551/577 nm. Unit size 1 umol.