Alexa Fluor™ 700 NHS Ester (Succinimidyl Ester) (C09-1510-711)

Alexa Fluor™ 700 is a bright and photostable near-IR dye that can be excited with a xenon-arc lamp, far-red diode lasers, or dye pumped lasers operating in the 675–700 nm range. Used for stable signal generation in imaging and flow cytometry, Alexa Fluor™ 700 dye is water soluble and pH-insensitive from pH 4 to pH 10. Fluorescence of this long-wavelength Alexa Fluor™ dye is not visible to the human eye but is readily detected by most imaging systems. In addition to reactive dye formulations, we offer Alexa Fluor™ 700 dye conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates optimized for cellular labeling and detection.The NHS ester (or succinimidyl ester) of Alexa Fluor™ 700 is the most popular tool for conjugating this dye to a protein or antibody. NHS esters can be used to label to the primary amines (R-NH2) of proteins, amine-modified oligonucleotides, and other amine-containing molecules. The resulting Alexa Fluor™ conjugate will exhibit brighter fluorescence and greater photostability than the conjugates of other spectrally similar fluorophores.Detailed information about this AlexaFluor™ NHS ester:Fluorophore label: Alexa Fluor™ 700 dye:Reactive group: NHS ester:Reactivity: Primary amines on proteins and ligands, amine-modified oligonucleotides:Ex/Em of the conjugate: 702/723 nm:Extinction coefficient: 205,000 cm-1M-1:Molecular weight: ∼1400:Typical Conjugation Reaction:You can conjugate amine-reactive reagents with virtually any protein or peptide (the provided protocol is optimized for IgG antibodies). You can scale the reaction for any amount of protein, but the concentration of the protein should be at least 2 mg/mL for optimal results. We recommend trying three different degrees of labeling, using three different molar ratios of the reactive reagent to protein.The Alexa Fluor™ NHS ester is typically dissolved in high-quality anhydrous dimethylformamide (DMF) or dimethylsulfoxide (DMSO), and the reaction is carried out in 0.1–0.2 M sodium bicarbonate buffer, pH 8.3, at room temperature for 1 hour. Because the pKa of the terminal amine is lower than that of the lysine epsilon-amino group, you may achieve more selective labeling of the amine terminus using a buffer closer to neutral pH.