Alexa Fluor 488 NHS Ester | CAS 1025894-97-6

Product Introduction

Alexa Fluor 488 NHS Ester is a bright green-fluorescent dye with excitation/emission at 494/517 nm, ideally suited for the 488 nm laser line. The NHS ester functionality enables covalent conjugation to primary amines of proteins, antibodies, peptides, and amine-modified oligonucleotides, forming stable amide bonds. The resulting conjugates exhibit high fluorescence quantum yield (~0.92), excellent photostability, and pH insensitivity across pH 4-10, outperforming spectrally similar dyes such as FITC. It is widely used for fluorescence microscopy, flow cytometry, FRET assays, immunofluorescence staining, and single-molecule detection applications.