N-succinimidyl compound

No incorporation of iodine If you did not forget anything in the iodination mix and did not add anything wrong, the protein either does not contain any tyrosine residue or the oxidation conditions were too weak. If other or stronger oxidizers (e.g., more chloramine T) do not help, you could try to convert with Bolton-Hunter reagent or H-marked N-succinimidyl compounds or you could attempt to iodize a histidine of the protein. 

During the incubation of the molecule that is to be marked with the H-marked N-succinimidyl compoimd, you need to keep in mind the solubUity of two molecules and the water sensitivity of the N-succinimidyl compound. Finally, the buffer or solvent being used may not contain any molecules with free amino groups. 

Fig. 5.12 On-line continuous-flow monitoring of bioactive compounds using fluorescein-biotin/streptavidin assay. MS instrument Q-ToF2 (Waters) equipped with a Waters Z-spray electrospray (ESI) source. Triplicate injections of (a) biotin-N-succinimidyl ester (m/z 342), (b) N-biotinyl-L-lysine (m/z 373),...

In the iodination of molecules with low MW, Na I usually serves as the source of and chloramine T as the oxidizer (molar ration of the three reactants about 1 1 1). A slightly basic pH of the reaction mixture favors the monoiodination. With compounds that are sensitive to water (e.g., N-succinimidyl derivatives), the iodination reaction is carried out in organic solvents (e.g., acetone, acetonitrile). The iodination efficiency depends on the solvent being used. HPLC or thin-layer chromatography separates free iodine, iodized molecule, and noniodized molecule. 

NBD fluorescent probe 87 was prepared from condensation between free amino derivative (S)-85 (n = 5) and NBD chloride in 76% yield. BODIPY derivative 88 was obtained starting from a condensation between the compound (5)-85 ( = 5) and BODIPY N-succinimidyl ester in 72% yield (Scheme 20). 

This compound has been synthesized by Nimura et al. [389]. In 0.5 M borate buffer, pH 9.5, it reacts with amino acids within 1 min at room temperature to form naphthylcarbamoyl derivatives. The rapid reaction and the removal of excessive reagent by hydrolysis make N-succinimidyl-l-naphthylcarbamate suitable for automated pre-column derivative formation [390]. The intense fluorescence (excitation at 290 nm, emission at 370nm) allows the determination of sub-picomole quantities. A HPLC system suitable for the separation of the commonly occurring amino acids has been worked out [390],... 

As an alternative to fluoride displacements directly on the compound of interest, many researchers opt for the development of molecules that have the ability be linked to a molecule that has efficiently been labeled with fluorine-18. Probably the most well known example of this class of fluorine-18 labeled linker capable molecules is the N-succinimidyl-4-[ F]fluorobenzoate ([ F]SFB). The prepa-ration of this reagent comprises a total of three steps beginning with the initial two step preparation of 4-[ F]fluorobenzoic acid ([ F]FBA) [9] and then finished off with the formation of the desireci succinimidyl ester (Figure 2) [10]. 

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