Extinction Coefficient Excitation Maximum: 162000;Fluorescence Quantum Yield: 0.1 Sulfo-Cy3 NHS ester an analog of Cy3)NHS ester, is sulfonated, hydrophilic, water-soluble and amino reactive dye containing NHS ester group. This reagent can efficiently label proteins and peptides in purely aqueous solution without any organic co-solvent and thus is Ideal for low solubility proteins and proteins prone to denaturation. Sulfo-Cyanine3 NHS ester can replace Cy3) Alexa Fluor 546, and DyLight 549.