Cy3B NHS Ester

Unit Size
Price (USD)
Cat.#: 1831-1
Unit size: 1 mg
in stock
Cat.#: 1831-5
Unit size: 5 mg
in stock
Cat.#: 1831-25
Unit size: 25 mg
in stock
Cat.#: 1831-100
Unit size: 100 mg
in stock

Cy3B NHS Ester is an improved version of Cy3 dyes with significantly increased fluorescence quantum yield and photostability.Cy3B Dye is a bright, water-soluble, and pH insensitive from pH 4 to pH 10 orange-fluorescent dye. Cy3B conjugates of antibodies, peptides, and proteins can be excited using the 532 nm or 555 nm laser line and visualized with TRITC (tetramethylrhodamine) filter sets. Cy3 conjugates give less background than TAMRA and most other commonly used fluorescent dyes.

The NHS ester (or succinimidyl ester) is the most popular amine reactive group for labeling with the primary amines of proteins (Lys), amine-modified oligonucleotides, and other amine-containing molecules. Cy3 NHS ester is not recommended for labeling proteins at high molar ration due significant self-quenching, and only recommended for detection of moderate-to-high abundance targets. For detection of low-abundance biological targets we recommend using AZDye 555 NHS Ester (Alexa Fluor ® 555 analog), which can be attached to proteins at high molar ratios without significant self-quenching, enabling brighter conjugates and more sensitive detection.

Primary amine
Abs/Em Maxima
560/571 nm
Extinction coefficient
120,000 cm-1M-1
Water, DMSO, DMF
Spectrally similar dyes
Cy3, DyLight® 555, Alexa Fluor® 555
Molecular weight
Storage conditions
Shipping conditions
Ambient temperature


Enter only one — either volume or amount of protein to be labeled
Enter only one — either maximum concentration of DMSO or volume DMSO added to label

Cy®Dye is a trademark of GE Healthcare.