Product Description: Cy3-PEG7-SCO is a dye derivative of Cyanine 3 (Cy3) (HY-D0822) containing 7 PEG units. Cy3-PEG7-SCO has a SCO group that can be covalently bonded to the amino group. SCO is often used to react with amino acid residues of proteins or peptides, particularly lysine.