Fluorescein 5(6)-isothiocyanate (CAS 27072-45-3)

Fluorescein 5(6)-isothiocyanate, commonly abbreviated as FITC, with the CAS number 27072-45-3, is a derivative of fluorescein, one of the most extensively used fluorescent dyes in the field of biochemistry and molecular biology for labeling proteins, nucleic acids, and other biomolecules. FITC is characterized by the covalent attachment of an isothiocyanate group, which is reactive towards nucleophilic groups such as amines, typically found in the side chains of lysine residues in proteins or the amino groups of nucleotides in nucleic acids. This chemical reaction forms a thiourea linkage, effectively tagging the biomolecule with a fluorescein moiety that exhibits strong fluorescence when excited by light at specific wavelengths (around 495 nm), and emitting a bright green light (around 519 nm). This reactive and fluorescent nature of FITC has made it a valuable tool in various scientific research domains. It is primarily used in fluorescence microscopy, flow cytometry, and ELISA (Enzyme-Linked Immunosorbent Assay) to visualize the presence, location, and quantification of tagged molecules in complex biological systems. Additionally, FITC′s applications extend to tracing cellular processes, studying protein interactions, and mapping neural connections. Its ability to act as a fluorescent probe has facilitated significant advancements in the understanding of cellular and molecular mechanisms under both normal and pathological conditions. The bright and stable fluorescence of FITC also enables its use in creating multicolored staining protocols by combining it with other fluorescent dyes, thus enhancing the resolution and depth of imaging studies in life sciences research.