Fluorescein-5-maleimide (ultra pure)

Fluorescein-5-maleimide enables protein labeling via thiol modifications in most proteins at cysteine residues that either are intrinsically present or resulted from reduction of cystine residues. Unlike iodoacetamides, maleimides do not react with histidine and methionine under physiological conditions. The probe is suitable for assessing conformation- dependent accessibility of cysteine residues in proteins. Wavelength Maxima: Excitation 493nm, Emission 515nm