Fluorescein-5-thiosemicarbazide

Other Names Spiro[isobenzofuran-l(3//),9 -[9//] xanthene], hydrazinecarbothioamide deriv. Fluorescein-5-thiosemicarbazide 5-FTSC FTSC FTZ  

Merck Index Number Not listed Chemical/Dye Class Xanthene Molecular Formula C21H15N3O5S 

Molecular Weight 421.43 Physical Form Yellow solid  

Solubility Soluble in water, A,A-dimethylformamide, dimethyl sulfoxide 

Industrial Applications Characterizing soft material interfaces understanding fibrous network structures in nanodevice preparation functionalizing/ encapsulatiing particles by initiated chemical vapor deposition (iCVD) functional polymer coatings high refractive index coatings papers  

---

Fluorescein-5-thiosemicarbazide is soluble in DMF or in buffered aqueous solutions at pH values above 7.0. The reagent may be dissolved in DMF as a concentrated stock solution before adding a small aliquot to an aqueous reaction medium. The compound itself and all solutions made with it should be protected from light to avoid decomposition of its fluorescent properties. 

Figure 9.10 Fluorescein-5-thiosemicarbazide reacts with aldehyde groups to produce hydrazone linkages.

To the purified, oxidized glycoprotein(s), add fluorescein-5-thiosemicarbazide to a final concentration of 0.5 mg/ml. 

The methods for using this reagent in labeling glycoproteins on cell surfaces or in solution are similar to those described for fluorescein-5-thiosemicarbazide, above. 

Fluorescein-5-thiosemicarbazide is a hydrazide derivative of fluorescein that can spontaneously react with aldehyde- or ketone-containing molecules to form a covalent, hydrazone linkage (Fig. 208) (Pierce). It also can be used to label cytosine residues in DNA or RNA by use of the bisulfite activation procedure (Chapter 17, Section 2.1). The resulting fluorescent derivative exhibits an excitation maximum at a wavelength of 492 nm and a maximal emission wavelength of 519 nm when dissolved in buffer at pH 8.6. In the same buffered environment, the compound has an extinction coefficient of approximately 78,000 M-1cm 1 at 492 nm. 

Generalized protocols for the use of hydrazine-probes reactive toward aldehyde residues can be found in Section 1.1. These procedures are directed at the labeling of cell surface glycoproteins or glycoproteins in solution. Substitution of Lissamine rhodamine B sulfonyl hydrazine for the fluorescein-5 -thiosemicarbazide reagent described in that section can be done without difficulty. Some optimization may be... 

Carbonylation occurs by the oxidation of some amino acid side chains into ketone or aldehyde derivatives by reactions with compounds of lipid oxidation or by glycoxidation with reducing sugars. These protein-carbonyl compounds are markers of protein oxidation, and recently, several carbonylated proteins and protein oxidation sites in milk (96), meat (97), and fishes (98) have been identified using a classical bottom-up proteomics approach based on 2-DE and MS/MS. Specific labeling of protein carbonyls using fluorescein-5-thiosemicarbazide has been developed and combined with 2-DE and... 

---