Sulfhydryls SAMSA-fluorescein

SAMSA-fluorescein, 5- [2(and 3)-5-(acetylmercapto)-succinoyl]amino fluorescein, is a fluorescent probe containing a protected sulfhydryl group. In its protected state, the compound is unre-active. The acetyl-protecting group can be removed by treatment with dilute NaOH at pH 10.0 (Figure 9.9). The resulting free sulfhydryl derivative can be used to label thiol-reactive crosslinkers or to couple with sulfhydryl residues on proteins and other molecules. After activating... 

Figure 9.9 SAMSA-fluorescein contains a protect thiol that can be deblocked by treatment with hydroxy-lamine. The reagent then can be used to modify molecules containing sulfhydryl-reactive groups.

To deprotect the acetylated sulfhydryl, dissolve the desired amount of SAMSA-fluorescein (Invitrogen) in lOOmM NaOH, pH 10.0, at a concentration of lOmg/ml. 

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