AZDye™ 405 NHS Ester (Alexa Fluor® 405 NHS ester equivalent) is a water-soluble, blue-fluorescent dye that is often used in multi-color applications, including flow cytometry and super-resolution microscopy using STORM. Its excitation is ideally suited for the 407 nm spectral line of the krypton laser or the 408 nm violet laser diode. AZDye™ 405 conjugates are pH-insensitive from pH 4 to pH 10.
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. Proteins can be labeled with AZDye™ 405 NHS Ester at high molar ratios without significant self-quenching, leading to brighter conjugates and more sensitive detection.