5-(N-Maleimido)fluorescein diacetate (CAS 150322-01-3)

5-(N-Maleimido)fluorescein diacetate, cataloged under CAS number 150322-01-3, is a specialized chemical probe extensively utilized in biochemical and biophysical research. This compound is a derivative of fluorescein, a widely used fluorescent dye, modified to include a maleimido group that provides specific reactivity towards thiol groups (–SH) found in cysteine residues of proteins. The diacetate groups attached to the fluorescein core render the molecule non-fluorescent and membrane-permeable, enabling it to freely enter living cells. Once inside the cell, esterases cleave the acetate groups, thus activating the fluorescence of the molecule and trapping it within the cell. The maleimido functionality then allows for covalent attachment to thiol groups, effectively labeling the thiol-containing molecules with a fluorescent tag. This mechanism is particularly useful in the study of protein localization, interactions, and dynamics within cells under physiological conditions. Researchers leverage this property for various applications, such as tracking the movement and distribution of specific proteins, investigating cellular processes in real-time, and elucidating mechanisms of protein function within the complex environment of a living cell. The specificity and brightness of 5-(N-Maleimido)fluorescein diacetate make it an invaluable tool in the field of molecular biology, where visualizing and tracking molecular processes are crucial.