Biotium offers high quality amine-reactive succinimidyl ester (SE, or NHS-Ester) dyes used to label proteins, oligonucleotides, and nucleic acids. We offer Cyanine 555 (Cy®3), Cyanine 647 (Cy®5), Cyanine 680 (Cy®5.5), and Cyanine 750 (Cy®7) as high quality succinimidyl esters. Also see our CF® Dye Succinimidyl Ester, available with more than 20 bright and photostable CF® Dyes.   Cyanine 680 is structurally identical to Cy®5.5 from GE Healthcare.    &lamba;Ex/&lamba;Em (water) = 681/698 nm  Dark blue solid soluble in DMF and DMSO  Store at -20°C and protect from moisture and light  C63H92N6O16S4  MW: 1318     Cy3, Cy5, Cy5.5, and Cy7 are registered trademarks of GE Healthcare.