Azido-fluorescein

Once the protein is modified to contain an alkynyl group at its C-terminal it can be used to covalently link to its click chemistry reactant partner, an azide on the surface of an array. Other azido molecules also can be conjugated with an alkyne-protein to facilitate the detection or capture of the protein using affinity techniques. For instance, an azido-fluorescein reagent can be used to detect fluorescently the expressed protein in complex samples or an azido-biotin... 

Figure 17.14 An expressed protein containing a thioester intein tag that was subsequently modified by native chemical ligation to contain an alkyne group then can be labeled using an azido-fluorescein probe by the click chemistry reaction in the presence of Cu1+.

A chemoenzymatic synthesis of the P-a-methyl 2 -deoxynucleoside triphosphates 122 has been described which involves reaction of the 5 -0-(methylpho-sphonyl)-N-protected nucleosides with pyrophosphate in the presence of CDI. Removal of the base protection by treatment with penicillin amidase gave compounds 122 leaving the labile a-methylphosphonate intact. A number of 2 -deoxythymidine 5 -triphosphate and 3 -azido-2, 3 -dideoxythymidine 5 -tripho-sphate analogues (123) containing a hydrophobic phosphonate group have also been synthesised and evaluated as substrates for several viral and mammalian polymerases. Some y-ester (124) and y-amide (125) derivatives of dTTP and 3 -azido-2, 3 -dideoxythymidine 5 -triphosphate (AZTTP) were also synthesized and studied. The y-phenylphosphonate triphosphate 126 and its conjugation to biotin and fluorescein labels has also been described. 

Pluronic P85 X 5 X Fluorescein, doxorubicin, etoposide, taxol, valoproic acid, 3 -azido-3 -deoxythymidine (AZT), loperamide Batrakovaet ah, 1999... 

The pseudodipeptide 55 (see Scheme 10.16) was regarded as a conformationally restricted Xaa-Pro dipeptide and Scolastico et al. functionalized the azido-group by copper(l)-catalyzed dipolar cycloaddition with an alkynylated sugar, biotin or fluorescein to afford substituted triazolyl-Xaa-Pro-dipeptide mimics 56 in good to excellent yields. ... 

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